Industrialization and urbanization are the necessary stages of social development, which not only significantly promote the reform and development of economic, social and even political structures, but also lead to changes in population structure, employment structure, land supply and demand and ecological environment. Among them, the most direct effect on land use is the conversion of agricultural land. Since the reform and opening up, the conversion of agricultural land has provided land guarantee for the all-round development of our national economy and played an important role in economic growth; However, on the other hand, there are obvious negative effects of farmland conversion, which leads to a large loss of farmland resources and a series of social, economic and ecological problems. Farmland conversion is an inevitable trend of economic development. However, because cultivated land is an irreplaceable natural resource, it not only has the economic value of production, but also has the social value of food security and ecological security. Whether a country can maintain a reasonable amount of cultivated land resources is directly related to whether it can realize the sustainable development of social economy. Therefore, most countries generally take various measures to intervene in the process of farmland conversion. Our government has been paying attention to the conversion of agricultural land, and has formulated the strictest farmland protection and land management system in the world to control it. In fact, through the investigation of the fluctuation cycle and economic development cycle of farmland conversion in China, it is known that there will still be cost losses in farmland conversion in China at this stage and for a long time to come, which has its reasonable side. But at the same time, it also hides more excessive losses: first, the market failure that is common in the process of land resource allocation; Second, there is still a serious government failure in the process of land resource allocation in China. The root of excessive losses caused by market failure lies in China's incomplete resource value system and the resulting price distortion of agricultural land resources, which leads people to ignore or rarely consider the hidden consumption of agricultural land resources with ecological and social values in the process of non-agriculturalization. Therefore, this paper takes this as a starting point, expands the non-market value system of agricultural land resources, and corrects the economic decision function of agricultural land conversion with the monetization accounting results of agricultural land resources, aiming at verifying the excessive loss of agricultural land conversion caused by market failure, looking for countermeasures to weaken the excessive loss, and providing theoretical and empirical basis for rational allocation of land resources. Firstly, this paper briefly introduces the background, research content and related basic concepts, paper structure, research methods and data sources, reviews the research trends of ecosystem service function, farmland conversion allocation and farmland resource value evaluation at home and abroad, and briefly comments on these existing achievements. Then, it combs the related theories of resource allocation and public goods, constructs an analysis framework of resource allocation efficiency, and applies it to the non-agricultural allocation of agricultural land resources, and analyzes the efficiency loss of non-agricultural allocation of agricultural land caused by market failure from the perspectives of market failure, loss of agricultural land value and excessive non-agriculture. Then, starting with the connotation of non-market value of agricultural land resources, the non-market value system of agricultural land resources is classified, and the evaluation methods of each non-market value are determined in detail. When calculating the non-market value of agricultural land resources, this paper takes Jiangsu, Hubei and Gansu, the representative provinces in the east, middle and west of China, as examples, and makes concrete calculations by using the substitute market method and the shadow price method. On this basis, using C-D production function, this paper constructs a model to measure the excessive non-agriculture caused by market failure, and makes an empirical test. Through the above research, the main conclusions are as follows: 1. Agricultural land not only has economic output function, but also has many important social and ecological service functions, and with the development of economy and society, the social and ecological service functions of agricultural land will be paid more and more attention. Based on the theory of modern resource value and sustainable development, and referring to the study of ecosystem services, it is considered that the social ecological service function of agricultural land is the natural environmental condition and effect that human beings depend on for survival, which is formed and maintained by agricultural land ecosystem and ecological process. The social and ecological functions of farmland can be subdivided into: atmospheric regulation, environmental purification, water conservation, soil conservation, nutrient circulation, biodiversity maintenance, recreation, culture and education, social security and social stability. It is precisely because this functional value of agricultural land cannot be directly reflected in the market price that the conversion of agricultural land use has a certain negative impact on the sustainable utilization of resources and the sustainable development of economy and society in the process of agricultural land conversion. In order to ensure the rational and sustainable utilization of agricultural land resources and the sustainable development of economy, monetary compensation should be made for the functional value of various social ecological services provided by agricultural land, so that this part of non-market value can be brought into the market system. The reason why the market failure leads to the excessive loss of farmland conversion is that there is no market for the social and ecological service function value of farmland, which leads to the failure of various control measures and means. In the process of farmland conversion, the market mechanism only plays an economic role, and the non-market value of farmland is excluded from the price system, leading to market failure. Judging from the price formation mechanism of farmland conversion, the service function of this part of farmland can not be traded through the market because of no property right or vague property right boundary, or because of the non-exclusiveness of consumption, and lacks the guidance of price signals, which easily leads to excessive waste or inefficient use of farmland conversion and loss of social welfare. Due to the defects of traditional market system and the publicity of social ecological service function of agricultural land, agricultural land protection can not rely solely on agricultural land regulation to a certain extent. In order to completely solve the problem of resource allocation failure caused by the social ecological function of agricultural land, the social ecological service value of agricultural land should be reflected in cost or price, and farmers should be encouraged to protect it by using incentive mechanism to enhance the status and importance of these service functions in the decision-making process of agricultural land conversion. 3. The social and ecological services provided by agricultural land are of great value, and the loss of agricultural land resource value is caused by market failure, and this loss of agricultural land value has certain regional differences. By calculating the non-market value of agricultural land resources in Jiangsu, Hubei and Gansu provinces, it is found that the non-market value of agricultural land resources in Jiangsu, Hubei and Gansu provinces reaches 659,800 yuan/hectare, 656,600 yuan/hectare and 632,900 yuan/hectare respectively. Among them, the ecological service value of unit cultivated land in Jiangsu Province is 224,000 yuan, the social security value of unit cultivated land is 224,300 yuan, and the social stability value of unit cultivated land is 2 1. 1.5 million yuan, accounting for 33.95%, 33.99% and 32.06% of the non-market value of unit cultivated land respectively. The ecological service value of unit cultivated land in Hubei Province is 209,700 yuan, the social security value of unit cultivated land is 232,800 yuan, and the social stability value of unit cultivated land is 2 1.4 1.00 million yuan, accounting for 3 1.94%, 35.46% and 32.60% of the non-market value of unit cultivated land respectively. The ecological service value of unit cultivated land in Gansu Province is 189500 yuan, the social security value of unit cultivated land is 261/000 yuan, and the social stability value of unit cultivated land is 182300 yuan, accounting for 29.94% and 4/kloc-0 of the non-market value of unit cultivated land respectively. From the analysis of the results, the non-market value of agricultural land resources gradually decreased from east to west, but the social security function of agricultural land gradually increased, mainly because the social security function of agricultural land was negatively correlated with the local economic development level and non-agricultural employment income. The only way to coordinate the contradiction between farmland protection and economic growth is to reasonably choose the number of farmland conversion. Theoretically, the optimal amount of farmland conversion should be determined according to the principle that the marginal income of land resources in non-agricultural sector and agricultural sector is equal. Combined with the actual process of farmland conversion in China, the cost loss of farmland conversion is a reasonable degree to promote the allocation of farmland conversion from dilemma to win-win. Through the empirical study of Jiangsu, Hubei and Gansu provinces, it is found that due to market failure, the excess loss I of farmland conversion in Jiangsu, Hubei and Gansu provinces is 47,642 hectares, 148 10 hectares and 5,542 hectares respectively, accounting for 3 1.77 of the actual farmland conversion. 12%, which shows that ignoring the non-market value of agricultural land resources causes serious waste of resources, and also shows the ecological fragility of the western region. In the process of economic development, the main function zoning should be carried out at the national level, and each region should be divided into different levels of development regions according to its different geographical location, ecological environment and development potential. Based on the above research results, this paper provides useful policy measures for improving the allocation efficiency of agricultural land conversion and correcting market failure in the future, including: implementing compensation mechanism for social and ecological protection of agricultural land; Implement the "green GDP" assessment method to change the incentive structure of local government's farmland conversion; Re-recognize the value of agricultural land resources and bring the non-market value of agricultural land into the compensation system for land acquisition; Actively promote resource value evaluation and innovation of public policy system; Clarify the main function zoning and optimize the regional land development pattern.