The 21st century is a brand-new period in which China has entered a new period in which industry feeds agriculture, cities support rural areas, and build a harmonious society. As an important part of national strategic security, food security is the foundation for building a new countryside and building a harmonious society, and has always been the focus of attention of the government and academia. From the current form of China's grain production, under the role of various agricultural policies, China's grain production has increased for 11 consecutive years since 2004, and the contradiction between domestic food supply and demand has been effectively alleviated. However, it is undeniable that there are still many problems in China's food security: the food circulation system is not perfect; There are regional and structural contradictions between food supply and demand; In the core grain production areas, the phenomenon of "increasing production without increasing income" occurs from time to time, such as difficulty in selling grain and low prices; The distribution of benefits between the main grain-producing areas and the main grain-selling areas is uneven, and the gap between regional economic development is widening; The price difference between raw grain and finished grain in production and marketing areas is too large, and the surplus of producers and consumers is damaged. The above factors have jointly led to low enthusiasm for grain and agricultural production, increased grain reserve costs, and reduced anti-risk ability in major grain marketing areas, neutralizing the improvement of national food security coefficient brought about by successive years of grain production. Food circulation is an important part of social commodity circulation, and it is also an important link connecting food production and food consumption. According to Marxist theory of political economy, circulation plays the role of converting commodity capital into monetary capital in the market. The peasants produce the multiplied grain through the production capital transformed by the production capital of the money capital through production labor, and the value of commodity grain can only be reflected after it enters the circulation link, and the peasants can also obtain the monetary capital of the multiplicated part. Consumer demand is the fundamental motivator that guides food production, but whether this motive can be obtained by farmers and converted into actual market supply depends on the efficiency of food circulation. This is in line with the view of distribution economics that grain circulation is regarded as a basic industry and a leading industry. Grain circulation determines the degree of commercialization and marketization of grain products, and is related to the vital interests of consumers; It directly affects food production, agricultural efficiency and farmers' income. From the current distribution of benefits in the operation of the grain market, grain circulation middlemen have become the largest interest group in the entire food industry chain, while the interests of food producers and consumers have been squeezed. Therefore, grain circulation has become an important factor affecting the growth of grain and agricultural income, restricting the development of agriculture and rural economy in core grain production areas, and protecting national food security. At the beginning of reform and opening up, the state carried out many reforms of the grain circulation system in response to changes in food supply and demand. From 1979 to 1984, the unified purchase and marketing of grain withdrew from the market, and the transition from planning regulation to the combination of planning and market was excessive. From 1985 to 1997, during the dual-track system of contract ordering, market purchase and price, the grain unified marketing system was dissolved, grain circulation was gradually liberalized, and the policy of "ensuring quantity and releasing prices" was introduced. Subsequently, the period of market-oriented reform of grain purchase and sales since 1998, especially in 2004, when the grain purchase market was fully liberalized, the status of grain brokers, an important member of the grain purchase and sales market, was recognized by law. Nevertheless, there are still many problems in China's grain circulation market: the market system is not perfect, the market information is not smooth, and the transaction cost of grain is high. In the period of further deepening of the market-oriented reform of the grain circulation system, the improvement of grain circulation efficiency should be based on the strength of the market itself, and the government should mainly play a guiding and auxiliary role to create favorable conditions for smooth food circulation. The "Twelfth Five-Year Plan" period is a period for deepening the market-oriented reform of the grain circulation system, and whether it can effectively solve many problems in the current grain circulation market will be directly related to the stability of the social price level and the level of national consumption during the "Twelfth Five-Year Plan" period. Under the conditions of market economy, all stakeholders in grain circulation are market decision-makers, and only when their respective interests are effectively guaranteed can they ensure that all links of grain circulation form a complete supply chain system and realize the smooth flow of grain from the core production area to the main sales area. However, affected by factors such as the imbalance of system and economic development, the unreasonable distribution of interests among various subjects in China's grain circulation has greatly hindered the smooth flow of grain. From the current distribution of interests in the grain market, middlemen have become the largest interest group in the entire food industry chain, while the interests of producers and consumers have decreased. Therefore, in order to increase the income of grain farmers, stabilize grain production, stabilize market food prices, and protect the interests of consumers, it is urgent to effectively control the grain circulation market and coordinate the distribution of interests among all entities in the grain circulation market. In order to solve these problems, relying on the project of the National Self-Science Fund "Research on the Coordination Mechanism of China's Grain Production, Circulation and Reserves in the Context of Food Security", with the funding of the Hubei Provincial Social Science Foundation, we set up a project to conduct a special study on the economic behavior of micro-subjects in the food supply chain from the perspective of circulation efficiency, and finally formed this book. This book first breaks down the various stakeholders in China's grain circulation market and their relationship with each other, and discusses the problems existing in the current grain circulation market from multiple levels such as the historical evolution of each subject, interest game, and food policy implementation. Secondly, a two-tier market model is constructed, the coordination mode of interests of various entities in the grain circulation market is analyzed, and the deep-seated reasons affecting the efficiency of the grain circulation market are explored from the theoretical level. At the same time, the survey data is used to measure the transaction efficiency, technical efficiency, scale efficiency and total factor productivity of grain circulation enterprises from an empirical perspective, and the current status and change trend of the current transaction efficiency and operational efficiency of the grain circulation market are analyzed. Finally, on the basis of comprehensive theoretical demonstration and empirical research conclusions, a policy system that coordinates the interests of all subjects in the grain circulation market in line with the actual grain production and circulation in China is designed. The main content of the book is divided into six parts. The first part focuses on the current situation of China's grain circulation market. Under the dual thrust of the gradual stabilization of grain production capacity and the deepening of the market-oriented reform of the grain circulation system, the focus of China's grain supply and demand security has gradually shifted from total security to regional supply and demand security relying on circulation. According to microeconomic theory, the fundamental to achieving the security of food circulation lies in coordinating the interests of market players. At this stage, there are still many problems in the coordination of the interests of China's grain circulation market entities: first, the immature development of market entities, which is not only reflected in quantity, but also in the economic strength of interest subjects; Second, the coordination between the grain purchase and sales market and grain production is ineffective, which is manifested in the imbalance in the distribution of interests between the main grain-producing areas and the main sales areas; Third, there is a conflict between the government's policy goals and the market-oriented operation of state-owned grain enterprises, and it is necessary to build a grain circulation system with Chinese characteristics. The second part is the economic analysis of the coordination of the interests of various entities in the grain procurement market. The two-tier market model was used to explore the relationship between grain farmers, private grain merchants, state-owned grain purchasing enterprises and other stakeholders in the grain purchase market, and the comprehensive effect of the minimum grain purchase price policy was analyzed. In the grain purchase market, the amount of grain purchased by enterprises is directly proportional to their transaction efficiency, that is, the higher the transaction efficiency of enterprises, the more food sources they can obtain. The inefficiency of grain purchaser transactions will have the following adverse effects: first, the reduction of producer surplus; Second, the purchase price and purchase volume given by grain buyers decreased, their competitiveness in the acquisition market declined, their profits in the sales market were limited, and the total profit obtained decreased; Third, the effective supply of the market is insufficient, consumers face high food prices, and consumer surplus decreases; Fourth, the cost of food purchase borne by society has risen, and national food security has not been guaranteed. Therefore, reducing market transaction costs and improving transaction efficiency is a breakthrough point for coordinating the interests of all entities in the grain purchase market and stabilizing market order. In theory, the implementation of the policy of minimum grain purchase price can achieve better economic and social benefits. The implementation of the minimum purchase price policy is unfavorable to consumers, but their economic losses will not be too great; For the country and society as a whole, transaction efficiency is improved, transaction costs are reduced, farmers' enthusiasm for growing grain is improved, and food security is guaranteed. The actual implementation of this policy has also been recognized by all sectors of society, but from the results of the author's research and empirical research, the proper performance of the minimum purchase price policy for grain has not been fully reflected, and the effect on the efficiency improvement of grain circulation enterprises is not significant. Therefore, answers remain to be sought outside the policy itself. The third part is the economic analysis of the coordination of the interests of various subjects in the grain sales market. This part first takes the circulation of grain ownership in the grain sales market as a clue to explore the relationship between various stakeholders in the market, and then uses the transaction cost theory to analyze the main factors hindering the cross-regional circulation of grain under the two conditions of sufficient grain sources and insufficient market grain sources. The study shows that: (1) in the grain sales market with the nature of a buyer's market, large grain purchasing and marketing enterprises that provide grain to the main grain sales areas tend to reduce the volume of grain in order to pay less transaction costs; (2) In a grain sales market with the nature of a seller's market, as the volume of food transactions increases, the marginal transaction costs paid by private grain merchants acting as food demanders continue to increase, and they will eventually refuse to buy more food, hindering the completion of market transactions. It can be seen that the entry point to promote the smooth completion of grain transactions in both cases lies in reducing the transaction costs of grain purchasing and marketing enterprises. Therefore, reducing the transaction costs of purchasing and selling enterprises and improving the transaction efficiency of enterprises is the key to promoting the smooth circulation of grain between production and marketing areas. The fourth part is to measure and analyze the transaction efficiency of grain circulation enterprises. This part uses Samuelson's "iceberg transaction cost" model to derive a transaction efficiency calculation model that only considers commodity price factors, which is used to measure the transaction efficiency of 21 grain circulation enterprises in Hubei Province in the three years from 2006 to 2008. By comparing the transaction efficiency value between enterprises, the fluctuation of interannual transaction efficiency of enterprises, and the transaction efficiency of enterprises enjoying preferential policies, the following conclusions are drawn: the overall transaction efficiency of the grain circulation industry is at a high level and is constantly improving, but it is still in an unstable tortuous improvement. The transaction efficiency gap between enterprises has a trend of narrowing, but the improvement of transaction efficiency of individual enterprises lacks stability, which is not in harmony with the improvement of the overall transaction efficiency level of the industry. The government's preferential policies for individual grain purchasing and marketing enterprises have not had a significant positive effect on improving their transaction efficiency. The fifth part is to measure and analyze the operating efficiency of grain circulation enterprises. The DEA method was used to calculate the technical efficiency, scale efficiency and total factor productivity of 21 grain circulation enterprises in Hubei Province from 2006 to 2009. The calculation results show that the allocation of resources and elements of most grain circulation enterprises is unreasonable, and the optimization process of factor allocation by enterprises is relatively arbitrary. The government's preferential policies for some enterprises have little impact on industry efficiency; Policy preferences and preferences can help improve the overall efficiency of beneficiary enterprises, but this positive impact is not sustainable; Over time, the gap between enterprises in the grain circulation industry has widened year by year, including economic strength and technical strength; Production based on increased technological efficiency in the food circulation industry is sustainable, but the scale efficiency is declining year by year; The sustainability of business operations is enhanced, but the trend is not stable. The sixth part is the design of the grain circulation market policy system. This part proposes the construction of a grain circulation mechanism from the perspective of coordinating and protecting the interests of market entities: the market-oriented reform of the grain circulation system under the government's macro-control, the government does not directly intervene in the market but has absolute influence on the grain market. The grain circulation policy system is based on the administrative functions of the state and consists of four parts: laws and regulations, supporting agricultural cooperative organizations, cultivating market players, and establishing a food subsidy policy system. The improvement of laws and regulations is the first layer of the role map of the policy system, which provides a legal environment for the market-oriented reform of the food circulation system, which not only has the mandatory implementation of laws but also strips away the direct intervention of the government in the market, which is helpful to solve difficult problems in the process of food security protection. Supporting agricultural cooperation organizations, cultivating market players, and establishing a food subsidy policy system are the second layer after laws and regulations, that is, the laws and regulations formulated by the state directly act on these three policy measures to promote the implementation of policy measures. At the second level, the food subsidy policy system has a direct effect on the development of IFAP and the cultivation of market subjects. This book comprehensively uses microeconomics, game theory and information economics, econometrics and supply chain theory, and adopts the method of combining qualitative and quantitative, literature research and research to study the coordination of the interests of various subjects in the grain purchase and sales market, and explore ways to improve the efficiency of the grain circulation market and coordinate the interests of all subjects. The innovation points are mainly reflected in the following three aspects. (1) Innovation in research perspective. Most of the existing literature on grain circulation efficiency in China starts from the macro level of grain circulation channel construction, logistics environment construction, system construction and improvement, and there are very few literature that studies the coordination of interests of various subjects in the food circulation link from the micro level of the supply chain - enterprise efficiency improvement. From the perspective of enterprise efficiency and micro supply chain intersection, this study studies the coordination of various stakeholders in the grain circulation link and the improvement of the efficiency of circulation enterprises. (2) Innovation in research methods. This book introduces the multi-layer market model into the grain circulation market, determines the two-tier market model that conforms to the characteristics of grain as a bulk commodity and China's grain production and circulation, and combines the relevant theories of microeconomics to analyze and demonstrate the difference in transaction efficiency between state-owned grain purchasing and marketing enterprises and private grain purchasing and marketing enterprises in the grain circulation market and its impact on market efficiency, so as to provide a theoretical basis for empirical research. (3) The study puts forward different views on the preferential performance of policies given by the government to purchasing and selling enterprises. Most existing domestic studies believe that the government's preferential policies for grain enterprises are conducive to improving the operational efficiency and transaction efficiency of enterprises. Based on the conclusions of empirical research, this book puts forward different insights: the government's policy preferences for individual grain purchasing and marketing enterprises have not had a significant positive effect on the improvement of enterprise transaction efficiency; The government's policy preferences and preferences have helped to improve the overall operational efficiency of beneficiary enterprises, but this positive impact is not sustainable.（AI翻译）