In November 2021，Zhaotong experienced two strong cooling weather processes．Using NCEP/NCAR daily reanalysis data，conventional observation data， this paper compares and analyzes the circulation situation，temperature advection，descending motion and water vapor conditions of the two processes．The results show that the different intensities of cold high pressure and cold advection result in different temperature drops；the influence of the stationary front will also cause the difference in cooling between the north and south of Zhaotong；strong descending motion is conducive to the transmission of high-level energy and the formation of ground gale；the height of the zero layer falling below 700hPa and the deep wet layer are conducive to snowfall，and the high ground temperature is not conducive to the formation of snow．