Improving food total factor productivity is a necessary way to break the double constraint of resources and environment, and promote the transformation of the food production system and the realization of the sustainable development goal of zero hunger. Based on the panel data of 729 counties in China from 2010 to 2019, this paper analyzes the effect of county financial marketization reform on food total factor productivity by using a two-way fixed effects model, focusing on the mechanism of the quality of factors such as land, labor and capital. The results show that county financial marketization reform promoted food total factor productivity growth by promoting technical progress, while technical efficiency did not play a significant role. Heterogeneity analysis shows that the effect of county financial marketization reform on grain total factor productivity is not significantly different in eastern and central China. There is a significant difference in the western region, where county financial market reform hindered the growth of grain total factor productivity. In terms of different functional areas of grain production, the facilitating effect is only played in the main grain production area, and the inhibiting effect is played in the main grain marketing area. Mechanistic analysis shows that the county financial marketing reform promoted the growth of food total factor productivity by improving the quality of labor and land, while the quality of agricultural capital has a masking effect. On this basis, it is necessary for the government to implement differentiated financial market-oriented reform strategies, and to guide and encourage county financial institutions to provide financial services to improve the quality of agricultural labor and farmland through tax incentives and loan interest subsidies.