Abstract: The integration of agriculture and tourism is an important content and implementing approach for promoting rural revitalization and deepening supply-side structural reform. It is also a major factor affecting the efficiency of regional farmland and agricultural production methods. Based on a panel data of 124 prefecture-level cities from 2010 to 2017, this paper evaluated the level of integration of agriculture and tourism and analyzed the heterogeneous impacts of the integration of agriculture and tourism on grain production efficiency by the fixed effect models with instrumental variable. Results show that the overall level of integration of agriculture and tourism is relatively low in China. The current level of development is relatively high in the eastern region, but the western region is developing rapidly. It is significantly heterogeneous for the impacts of the integration of agriculture and tourism on China's grain production efficiency. The efficiency of grain production is relatively high in economically developed regions. The integration of agriculture and tourism has significantly improved the efficiency of grain production by increasing the input of agricultural fixed assets and promoting the "return" of labor in non-major grain production areas, while the development of rural tourism has a significant "crowding effect" on labor and farmland resources in major grain production areas. The integration of agriculture and tourism with mountainous areas has more significant effects on labor mobility and rural fixed assets than those in the plain areas. In summary, this paper suggests increasing the development of leisure agriculture in impoverished mountainous areas, optimizing the allocation of agricultural fixed assets in non-main grain production areas, and improving the quality of rural tourism services in economically developed areas.