[Objective] The snowmelt runoff process of Songhua River was analyzed, and the influence factors of snowfall, such as temperature, radiation, and so on, were addressed in order to provide some basises for the regulation and utilization of snowmelt runoff in the Songhua River Basin.[Methods] Using methods of Mann-Kendall test, moving average and slope estimation, the tendencies and variations of snowfall, temperature, radiation, runoff and other information of Songhua River Basin from 1956 to 2010 were analyzed.[Results] (1) Runoff of spring thaw period was between 1.26×10⁸~1.20×10¹⁰ m³/a, and had a decreasing tendency; (2) Temperature rose significantly within the thaw period, increased by 0.047℃/a, which is greater than the increase of annual average temperature of 0.036℃/a; (3) Radiation value showed a trend of decrease in the study period, the yearly averaged decreasing rate and the corresponding value at frost free period droped by 5 J/(m²·a) and 8 J/(m²·a); (4) Snowfall increased year by year. The snowfall along the main stream decreased from east to west. While the snowfall along the branched Nenjiang River reduced from north to south gradually. Snowfall and snowmelt runoff changed at a same step.[Conclusion] The increased temperature not only makes a favorable condition for snow melting but also will enhance the evaporation. The increase of snowfall is not enough to counteract the effects of temperature on the snowmelt.