Abstract: Based on monthly climatic data from 1961 to 2000, the changing characteristics and trend of agroclimatic elements in Songnen Plain were studied. Results showed that, under the circumstances of global warming, during the past 40 years, the average annual temperature increased obviously and the warming speed was above 0.4℃/10a. After 1980, the warming trend was more obvious. The average air temperature in every season and in cropping season increased significantly. The average temperature in winter increased with the biggest ratio. The annual and winterly average maximum temperature increased with obvious trend. The annual, seasonal, and cropping average minimum temperature added significantly. Among which, the increasing ratio of average minimum temperature in winter and in spring were larger. For annual rainfall and the rainfall in 4 seasons, there was no obvious trend to increase or to decrease. However, during the period 1961-1980, rainfall in cropping season decreased significantly. The study results could be of interest for crop planning and cropping structure adjustment in Songnen Plain.