Abstract: The climatic change characteristics of cold waves and atmospheric circulations in Yunnan are analyzed, based on the daily mean temperatures and minimum temperatures of 125 meteorological observation stations in Yunnan Province from 1981 to 2021. The results indicate that: ① The cold wave frequencies in Yunnan show a decreasing trend from 1981 to 2021. In the province, cold waves happen most frequently in December and the following January; and most of the cold waves are a minimum temperature type. ② More frequently the cold waves will happen in Yunnan, when the polar vortex is stronger than normal, the Baikal blocking high is stronger than normal, the deep East-Asian trough and the Southern Branch trough are stronger than normal, the West Pacific subtropical high is weaker than normal and the East-Asian surface cold high is stronger than normal. ③ The cold waves along the Northeastern route and those along the Eastern route account for more than 90% of all the three routes of cold waves in Yunnan. The frequency of cold waves along the Northwestern route is the lowest, usually accompanied by a sharp drop to the lowest temperature, which often leads to severe frost weather in Yunnan. Most of the cold waves along the Northwestern route occur in the middle and late stages of the Eastern route cold waves. ④ Compared with the cold waves along the Eastern route, the surface cold high of cold waves along the Northwestern route in Yunnan extends westward and is stronger, the Southern Branch trough extends eastward, the upper cold advection is stronger, the wind speed in the low latitude westerlies is slower, and the downdraft in the Southeast of the Tibetan Plateau is stronger.