Using the Micaps system routine data and NCEP/NCAR reanalysis data, a comparative analysis of the two cold wave weather processes in Qiannan in February 2017 and March 2016 revealed that they have the same similarities: the temperature in the middle low trough cold center is below -40 ℃, it is the key condition that the two cold wave intensity are close to each other. The water vapor flux divergence zone and the vertical velocity rise zone correspond to the precipitation center distribution, and the precipitation phase changes from rain to snow after 1-2 days of cold air influence. The difference: the large difference in the strength of the cold high-pressure center of the ground Mongolia does not cause significant differences in the characteristics of cold wave drop and minimum temperature. The occurrence of hail time and regional and CAPE values are not necessarily corresponding.