Abstract: In order to study the evolution characteristics and influence factors of meteorological elements and the forming causes of snowstorms, a snowstorm disaster weather process that occurred during March 3rd-4th, 2007 was analyzed by using conventional meteorological data, satellite cloud image and numerical forecast products, etc. The results showed that the key factors that inspired such disaster weather were favorable large-scale circulation, abundant water vapor conditions, coupling of upper-lower jets, confluence of cold and warm low-level jets, strong upward movement and momentum downwash role. Some experiences and indices were summarized by analyzing the big snowfall process and it was applied in the forecast in the future, so as to provide reference basis for the forecast of rainstorm in the future.