Abstract: The diagnostic studies for the features of spatial and temporal distribution of the annual mean thunderstorm in China are made with EOF and main function analysis by using 30 year data from 104 observational stations. Results show that the distribution of thunderstorm in China is divided into 4 regions. The highest is in South and Southeast of China, the second in Tibet plateau and where nearby it, the third in North and center of China, the lowest in Northwest of China. The variation of first loading vector of the annual mean thunderstorm has spatial consistency.The variance ratio contribution of the first principal component is about 35.1%. However, the thunderstorm frequencies under different geographical conditions are of difference. Analysis indicates that the general trend of the annual mean thunderstorm change has been reducing for the last 30 years.It is obvious that the thunderstorm frequency became little over the majority region in 1980s except the Northeast part of the Northeast region and the Northwest part of the Xinjiang province.