Agricultural mechanization is an important foundation for realizing modern agriculture and ensuring food security. Based on the provincial panel data of China from 2001 to 2020， this paper empirically analyzes the impact of labor price on the mechanization of grain production and the output effect of grain production mechanization， and examines the differences of these impacts and effects at different stages of grain plowing， sowing and harvesting. The results indicate that the increase in labor price has a significant positive impact on the mechanization level of grain production， plowing and harvesting. Moreover， the total power of agricultural machinery has a significant spatial spillover effect on grain output and the power of large and medium-sized agricultural machinery， as well as the power of large and medium-sized agricultural machinery for plowing， sowing， and harvesting all have significant direct impact and spatial spillover effect on grain output where the spatial spillover effect is greater than its direct effect. It is suggested that we should try to achieve breakthroughs in the weak stages of grain production， actively promote the development of agricultural socialized services， and promote the rational flow and scientific allocation of agricultural machinery resources among provinces， strengthen the connection between smallholders and modern agriculture， so as to accelerate the realization of the whole process mechanization of grain production and agricultural and rural modernization.