Abstract: Based on the conventional high altitude and surface meteorological observation data of 13 national surface meteorological observation stations in Aba and the 6-hour reanalysis data of NECP, this paper analyzes the regional heavy snow weather process in Aba from 20:00 on March 15 to 20:00 on March 16, 2020, finds out its circulation background characteristics, and discusses the causes of strong snowfall and strong cooling. It is concluded that the main influence systems of snowfall weather in this process were the 500 hPa shear line maintained for a long time and the 600 hPa low vortex and shear convergence system, and the cooperation between the high-level and low-level systems was good. At the same time, the ground cold air played an important role in cooling and snow intensity enhancement. Strong snowfall was formed under the conditions of good cooperation with high-level and low-level weather system, good upward movement and relative humidity, long-lasting water vapor transport and water vapor convergence, certain intensity of invading cold air and appropriate temperature. The strong cooling was produced under the premise of high basic temperature in the early stage, combined with a certain intensity of cold air and continuous snowfall.