Abstract:The data of daily thunderstorm in Jiangmen City during 1961-2010 and the other twenty cities of Guangdong Province during 1971-2010 are used in the study of the high frequency period of thunderstorm， through the method of frequency analysis and the principal component analysis (PCA). The results show that, the climate characteristics of thunderstorms in Jiangmen City have the high correlation with the other cities of Guangdong Province, and the thunderstorm’s climate law is of the very strong representative in Guangdong area. The high frequency period of the thunderstorm is concentrated in the April-September period. Furthermore, it can be divided into the early phase (April-June period) and the later phase (August-September period), and July is a transition period. The climate change trend of the early phase high frequency thunderstorm is dropping first and then rising, with the abrupt change year being 1983. It is corresponding to the abrupt change of the atmospheric circulation in the westerly zone at the beginning of 1980s. Analysis of pentad scale reveals that the abrupt change occurs at the fourth pentad in May, just the South China Sea summer wind outbreak period.