Implementing the Provincial Governor Responsibility System for Food Security is not only crucial for consolidating the foundation of food security and ensuring its stability but also serves as an important exploration in advancing the modernization of the national governance system and governance capacity. This paper constructs a multi-task principal-agent model to analyze how central government performance assessment affects local officials’ governance decision-making between economic development performance and food security assurance. Utilizing panel data from prefecture-level cities across China from 2010 to 2020， this paper establishes a difference in differences model to examine the impact of the Provincial Governor Responsibility System for Food Security on the imbalance of “Grain-Economy” development. The study finds that the Provincial Governor Responsibility System for Food Security significantly alleviates the imbalance in local “Grain-Economy” development， and this conclusion remains robust after a series of robust tests. Heterogeneity analysis of local comparative advantages suggests that this mitigating effect varies due to differences in natural， technological， and market factors， being more significant in regions with flat terrain， high levels of agricultural socialized services， and a greater number of new agricultural business entities. Heterogeneity analysis of officials’ risk costs reveals that this alleviating effect is more prominent in regions where food security work entails relatively lower risk and where officials exhibit lower risk aversion. Therefore， it is recommended to further delegate food security responsibilities， formulate differentiated performance assessment weights for food security， and improve supporting policies for grain security to enhance local enthusiasm for grain cultivation and grain production.