Abstract: By using crop growth trends statistics model, the impacts of temperature and precipitation variations on the potential productivity of three main crops (rice, maize, soybean) in China from May to September are calculated and analysed, and the relationships between temperature, precipitation of each station and potential productivity are set up, respectively, which would be used to assess the impact of temperature and precipitation variations on crop yield of the same year, and the possible impact of future climate change on crop potential productivity in Northeast China.