Using the data in 71 meteorological stations in Northeast China,the photosynthesis potential productivity,the photosynthesis-temperature potential productivity and the climatic potential productivity of the main grain crops（maize,rice,soybean） were calculated by the step by step revisal method.Impact of temperature and precipitation to climatic potential productivity was discussed.Photosynthesis-temperature potential productivities and climatic potential productivities of the main grain crops in Northeast China showed a significant difference in the different sites,which led to an increase of the climate potential productivity from northwest to southeast gradually.The results also showed that maize was most adaptable in plain of Jilin Province,rice was best grown in southeast Liaoning Province,and soybean was better grown in north and east of the region which is cold and rainy.