Abstract: In order to dig the grain increasing potential of Heilongjiang Province and realize the sustainable development of production, reasons of grain yield increase per unit area were summed up as national policy, production condition, technical progress and the warming climate. Four indexes including sowing ratio of highly-yielding crops, total power of agricultural machine per unit area, amount of fertilizer and ≥10℃ active accumulated temperature were chosen to conduct the analysis. Using the methods of data processing at different times and grey correlation analysis, contribution of the above reasons to the grain yield increase per unit areawere investigated. The results indicated that the main reason of the grain yield increase per unit area was the national policy which leaded to the high cultivation proportion of highly-yielding crops, followed by the improvement of production condition and technical progress, warming climate. Based on the results, aiming at the problems involving in grain production of Heilongjiang Province, countermeasures including ensuring a steady state grain purchase policy, accelerating the industrialization of grain, paying attention to disaster prevention, constructing the new type system of modern agriculture, building the reasonable crop rotation system, increasing the yield per unit area and maintaining the total yield and so on were proposed to accelerate the development of grain production.