The thermal resources significantly increased in Heilongjiang plantation area due to the global climate change; therefore the feasibility of a barley-buckwheat double cropping system instead of a single cropping system in Heilongjiang was analyzed from the aspect of ecological suitability. According to the past studies, the suitability value was calculated using temperature, precipitation, sunshine and ecological suitability model. The correlation analysis between the ecological suitability and the relative meteorological yield was conducted to determine the critical value of crop production. the grid producing barley-buckwheat double cropping ecological suitability maps were made based on the reduction rates of 0, 15% and 30%, indicating that some regions in Heilongjiang Province have the ecological conditions for planting the double crops. Compared with the traditional planting pattern, there were obvious economic advantages in the double cropping system under one irrigation scenario. According to the analysis of social need and labor need, the barley-buckwheat model would be of high popularization in Heilongjiang Province.