Abstract: Based on panel data from 30 provinces and cities in China from 2003 to 2021, this study first measures the grain production efficiency of each province using the SBM super-efficiency model. Then, a double fixed-effects model is applied to study the total impact of the hollowing-out of the rural labor force on grain production efficiency. Subsequently, a mediation effect model is used to investigate the mediating effect of planting structure. Finally, the spatial heterogeneity in regions with different levels of mechanization and land scale management is empirically analyzed. The study finds that the total effect of the hollowing-out of the rural labor force on grain production efficiency is positive, while the direct effect is negative. Planting structure serves as a mediator in the impact of the hollowing-out of the rural labor force on grain production efficiency. In areas with higher levels of mechanization, the hollowing-out of the rural labor force is more beneficial to grain production efficiency. In regions with lower levels of land scale management, the hollowing-out of the rural labor force has a more significant positive effect on improving grain production efficiency.