Based on the data from the national meteorological stations in the northeastern QinghaiTibet Plateau, the occurrence frequencies of monthly, quarterly and annual strong cold air for each station and the entire region from 1961 and 2015 are calculated, and then we analyzes the characteristics of strong cold air and its influences with the climate diagnosis method. It is found: In terms of spatial scale, from 1961 to 2015, there were strong cold air averagely in 20 stations collected throughout a year, 11 stations in spring, 17 stations in summer, 12 stations in autumn and 8 stations in winter, showing a significant decline. In terms of time scale, from 1961 to 2015, the annual occurrence frequency of strong cold air influencing the northeast QinghaiTibet Plateau decreased by 0.401 per 10 years, showing an obvious decrease tendency. In addition, the occurrence frequencies of strong cold air in summer and autumn in this region decreased by 0.094 and 0.119 per 10 years, respectively, also presenting a significant decline. However, the annual strong cold air events in spring and winter were decreased by 0.087 and 0.076 time per 10 years, respectively, without significant decline. Moreover, the occurrence frequency of strong cold air in the northeastern QinghaiTibet Plateau showed a significant decline from 1983 to 2014 and insignificant decline from 1962 to 1982. With respect to its influence, the annual occurrence frequency of strong cold air in the northeastern QinghaiTibet Plateau reduced due to the significant increase of average minimum temperature and a significant decrease in the number of strong wind days from 1961 to 2015.