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Based on the daily maximum temperature data from the Mapoling weather station in Changsha in recent 64 years, with the criteria for recognizing heat wave events, a statistical analysis is conducted on the characteristics of heat wave events over Changsha, so as to strengthen the people’s awareness of heat wave events, and make scientific emergency plans in advance. The study shows that: (1) The numbers of annual averaged high temperature days and heat wave events are 30.6 and 2.16, respectively; high temperature days are more common between June and September than other months; and July is the hottest month. (2) The frequency and intensity of heat wave show a stepwise variation characteristic in the last 64 years: the frequency is basically stable or slightly increasing (strengthening) from the 1950s to the middle 1960s, followed by a decreasing (weakening) from the 1970s to the late 1990s years, and after 2000, significantly increasing; the intensity is also strengthening. (3) The study also found that the urban heat island effect has intensified the heat wave intensity to some extent after 2000.