Using the data of the thunderstorm days of Danzhou stations in Ha inan province from 1971 to 2000, the basic climatic characteristics of thunderstorm in Danzhou are analyzed. It is shown that the annual averaged days of thundersto rm in Danzhou are 111. Thunderstorm occurs frequently from May to August, most f requently from 13-17 in the afternoon . The general trend of the annual thunde rstorm in Danzhou has been reducing in the last 30 years. Based on the thunders torm data from 1991 to 2000, the related circulation patterns and synoptic syste ms are also studied. The synoptic patterns of thunderstorm can be divided into f ive types, which are affected by the cold air, indifferent cold high, the subtro pical high ,the tropical cyclone or related to tropical low systems respectively. The proportion of each type varies in different seasons.