Abstract: As Chinese core region of grain production, the major grain area plays an important role in guaranteeing food security in China. Therefore it is full of meaning to research spatiotemporal differentiation and evolution characteristics of grain climatic production potential in Chinese major grain area, especially under the background of climate change. Using step correcting mechanism model based on daily monitoring data of 341 meteorological stations in 13 provinces of Chinese major grain area, this study investigates grain climatic production potential and its spatiotemporal evolution from 1981 to 2015. The results indicate that: （1) The annual average grain climatic production potential in Chinese major grain area is 9 171.17 kg/hm², and temporal evolution path of grain climatic production potential in Chinese major grain area is generally stationary, however photosynthetic production potential has been decreasing and light-temperature production potential has been raising. The variation of light, temperature and water climatic resources has a little comprehensive effect to Chinese grain production. （2) Photosynthetic production potential determined by illumination in the northwest is higher than in the southeast, however spatial structure of grain climatic production potential reorganizes after continuous superposition of light, temperature and water climatic resources. Grain climatic production potential in Chinese major grain area exhibits a significantly spatial pattern, characterized by higher in the southeast than the northwest. Further, the higher potential areas are mainly concentrated in the Plain of Yangtze River Middle and Lower Reaches and Chengdu Plain, where climate and terrain condition is suitable for cultivation. （3)The evolution of grain climatic production potential in Chinese major grain area has three characteristics. The first characteristic is that scope of the higher potential areas has been narrowing; the second is that scope of the lower potential areas basically holds; and the third is that spatial disparity in the medial potential areas has been weakening.