Abstract: Sanjiang region is in Heilongjiang Province in the northeastern part of china, its area is about 106800 km2. It is now an important regian of grains and one of the major reclamation areas in northeastern China.In this paper, the solar light and thermal resource in San jiang region are analyzed with the emphasis on the photosynthesis-temperature productivity. By considering the influence of temperature on the potential productivity of various crops, we suggested an empirical formula for estimating the temperature-influence parameters of C4-crops, C3-cool season crops and C3-hot season crops.On this basis, the potential productivity of the lour major crops (spring wheat, soybean, maize and rice) are estimated in Sanjiang region.Finally, sorle questions related to the exploitation and utilization of the solar light and thermal resource in Sanjiang region are discussed.