Based on the daily surface temperature data at 384 stations of China and the NCEP/NCAR daily reanalysis data from 1960 to 2010,this paper analyzes the frequency and intensity characteristics of cold air activity in China.Results show that both frequency and intensity of cold air activity at single station in northern China are higher than those in southern China.Based on the invading routes of cold air,northern China is divided into three subareas,in which the most cold air activity occurs in November,and southern China is divided into two areas by 25°N,in which more cold air occurs in December and January.On the interannual scale,both frequency and intensity of cold air activity decrease.On the interdecadal scale,the frequency variations of cold air activity in the five areas are inconsistent,while the intensity variations weaken from 1960s to 1980s.The frequency of nationwide cold air activity decreases in both 1960s and 1990s,while the interdecadal variation of northern cold air activity frequency is weak.Compared with the normal years,when Eurasia surface cold high pressure strengthens(weakens),surface temperature in most parts of China decreases(increases) and East Asia trough strengthens(weakens) at 500 hPa,the frequency of cold air acitivity is higher(lower) in the corresponding years.