Abstract: Potential crop productivity is important for evaluating agricultural climate resources. This study calculated the climatic potential productivity (CPP) of three grain crops (rice, maize, and winter wheat) using meteorological data. Daily measurements from 1961 to 2018 from 63 meteorological stations (Sichuan Basin, China) and crop phenology data from 1981 to 2018 from 46 agricultural meteorological stations were used to analyze productivity. Climatic factors, such as radiation, air temperature, and precipitation, and the effects of climate change were evaluated to provide regionally specific guidance for increasing agricultural productivity and sustainability. The results showed that the rice CPP in the Sichuan Basin increased from west to east between 1961 and 2018, the maize CPP was higher in the north and southwest, and the CPP of winter wheat was higher in the north and south. Reduced radiation negatively affected the CPPs of three crops, and higher temperatures positively affected the crop CPPs. Precipitation was the dominant climatic factor, affecting the spatial change of the CPP. Increased precipitation positively affected the crop CPPs, and decreased precipitation negatively affected the CPPs. The impact of climate change on the rice, maize, and winter wheat CPP was variable (positive in some basin areas, but negative in others); the overall effects of climate change on the CPPs were 0.5 kg·hm^-2·a^-1 for rice, -1.4 kg·hm^-2·a^-1 for maize, and 9.9 kg·hm^-2·a^-1 for winter wheat. Improving the selection of photosynthetically-efficient and drought-resistant crop varieties and crop field management are needed for climate change adaptation and to ensure food security.