Abstract: In order to assess the effects of climate change on grain production, find out the internal relations between them and guide local agricultural activities, the author analyzed the variation tendency of 3 main climatic factors (average temperature, precipitation and sunshine duration) in recent 21 years in Yibin City. The results showed that all the 3 factors had an increase tendency, and the fluctuant range of sunshine duration was comparatively small. The grey correlation analysis method was used to analyze the effects of climate change on grain yield. The results showed that the precipitation had the biggest influence on wheat yield with the correlation degree of 0.869; sunshine duration and per unit area yield had the biggest relevance with the correlation degree of 0.736. Therefore, climate change influenced grain yield significantly, especially climate yield. The results could provide basis for agricultural deployment.