Abstract: The paper aims to study the spatio-temporal variation characteristics of extreme climatic events in Hainan. Based on the daily temperature and precipitation data of 21 stations in Hainan from 1977 to 2017 provided by the Agricultural Meteorological Service System of Hainan and 16 extreme climatic indexes (ECI), we calculated the linear trend of ECI at each station and conducted the trend and mean mutation test of ECI sequence, defined the extreme climate variability index ( ECVI ) and clustered the stations. The results showed that: the frequency and intensity of warm events in Hainan increased, the intensity of cold events decreased, and their frequency decreased as a whole; the frequency and intensity of extreme precipitation events generally rose; the regional difference of drought events was large, mainly with enhancement; there was no significant trend reversal of ECI at each station during the research period; the mean value mutations of warm events occurred the most, followed by cold events, while the precipitation related ECI mean value mutations occurred the least. Qionghai, Qiongshan and Sanya had the most mean value mutations, while Changjiang, Xisha and Dingan had the least mutations. The cluster results showed that the 21 stations could be divided into 2 classes and 4 discrete points.