This paper analyzed the spatiotemporal patterns of thermal resources and of temperature suitability of maize at its different growth stages in Northeast China, based on the 1951-2100 daily mean and minimum air temperature from RegCM3. In 1951-2100, the thermal resources in Northeast China had an obvious persistent increase, the first day of temperature > or = 10 degrees C continued to be advanced, and the north boundary line in the zone of the first date of temperature > or = 10 degrees C before April 25th moved eastward and northward. In 2071-2100, the first date in some areas of Liaoning Province would advance to March 26th, and the areas with active accumulated temperature > or = 10 degrees C more than 3000 degrees C x d, the length of growth season, and the areas suitable for late-maturing maize planting in Northeast China would increase persistently. In the region, the mean annual temperature in 2011-2100 would be 3.34 degrees C higher than that in 1981-2010. In 1951-2100, there was and would be an increasing temperature suitability of maize at its sowing-heading stage. In 1951-2040, the maize temperature suitability at heading-maturing stage and in whole growth season was and would be higher in Liaoning Province than in Heilongjiang Province; in 2041-2100, the maize temperature suitability at heading-maturing stage and in whole growth season would decrease gradually in Liaoning Province but increase gradually in east Jilin Province and Heilongjiang Province.