Abstract: China has experienced successive high grain output while the central government has not reduced its attention to food security, continues to consolidate grain production capacity to respond to rigid demand growth based on its own. This paper summarizes the trend of grain production structure and the changes of input allocation in recent years and analyzes the grain production technology transformation and yield potential. Results show that land, water and cost-benefit are strong constraints on grain production. China should rely on technological path breakthrough and larger-scale services and operations to improve the marginal returns of inputs. Even the schedule of technological breakthrough is uncertain, there is still much room for per unit yield growth of main grains, especially corn. According to the increasing trend of unit yield, the contribution rate of each variety and the production situation of previous 3 times of 50 million tons increase. the paper makes 2 scenarios of production capacity upgrade: 1) if the average annual unit yield growth rates of rice, wheat and corn are 0.7%, 1.0% and 0.8% respectively, China will realize 700 million ton production capacity in 2026 and the sowing area can be reduced by about 0.5 million hm²; and 2) if the growth rates of rice, wheat and corn are 0.2%, 0.3% and 0.4%, respectively and the reduction of sowing area of 1.41 million hm², the production capacity upgrade can be realized in 2035. Currently, the key to ensuring the stable growth of production capacity lies in whether the large-scale services and operations, breakthrough in seed breeding and the construction of farmland quality could be substantially promoted.