Abstract: According to the national standard GB/T 20484-2017 of the People's Republic of China, based on the daily minimum temperature data of 97 stations in Hunan Province during 1961-2016 years, the statistical analysis of cold air activity characteristics in Hunan province shows: (1) The activity cycle of the cold air affecting Hunan is 3-4 d. It is mainly weak cold air, and is 87.4% of the total times. The strong cold air and cold wave are mostly in winter and spring. The frequency of cold air influence is more in the north than in the south in space, and the strong cold air influence is opposite. (2) The spatial distribution of cold air influence in Hunan is the obvious seasonal change. From January to may and October to December, the number of cold air decreases from north to south; June and September are adjustment periods; From July to August, the spatial distribution of cold air impacts is increasing from north to south. (3) There was no significant change in the number of cold air impacts in Hunan Province during 1961-2016, but the interdecadal variation was obvious. The times of severe cold air influence showed significant decreasing. (4) The cooling range of the cold air process in Hunan Province showed significant decreasing during 1961-2016; The duration of the cold air process presented insignificant increasing. The duration of the cold air influence process in Hunan was in 5d. The proportion of cooling air temperature greater than or equal to 8℃, 10℃, 12℃ of the cold air lasted for 3 d was the largest. (5)Compared with 1961-1980, the average cooling range in the most counties (cities) of Hunan was decreasing during 1981-2010, and the average duration of cooling was increasing.