Based on Two Dimensional Video Disdrometer, combined with cloud radar, wind profile radar, microwave radiometer, GPS/MET water vapor and other vertically-scanning instruments, the microphysical characteristics of a cold front snowstorm in The West Tianshan Mountain on February 18-19, 2020 were analyzed and studied. A classification algorithm for snowflake and graupel is designed to quantitatively study the microphysical characteristics of snowfall. The results show that :(1) In the cold front invasion and dynamic forcing stage, the precipitation particle type is mainly snowflake, and the microphysical process is deposition and aggregation; (2) In the stage of cold front control bring wind chill, precipitation particles are snowflake, graupel, and the microphysical processes is aggregation and riming, and aggregation is positive impact to riming; (3) In the passage of the cold front, due to the rise of cloud top temperature, less ice nucleation and enough subcooled water favor the riming. Different from the Nanjing, snowflake diameter and snow intensity in the West Tianshan Mountains are smaller, but graupel have a greater contribution to the snow intensity. The raindrop size distribution and gamma distribution are fitted by two melting models, which are similar to the characteristics of local stratiform cloud precipitation.