Abstract: By using the statistic methods in epidemiology, this paper analyzed the characteristics of high temperature and heat wave in Nanjing City and their impacts on local human health, based on the meteorological data from June to September, 1951-2009, the daily death toll from June to September, 2005-2008, and the hourly emergency treatment amount of heatstroke symptom from June to September, 2005-2007. Nanjing is a city with frequent occurrence of various levels high temperature and heat wave. In past 60 years, the average yearly high temperature days and harming high temperature days were 14.5 d and 1.1 d, and the average yearly heat wave and strong heat wave weather process occurred 1.9 times and 0.8 times, respectively. When heat wave happened, the excess mortality rate was higher than 20%, and this mortality rate was slightly higher for females than for males. Heat wave had greater damage on the sufferers of coronary heart disease and cerebrovascular disease, with no lag effect. Due to the human body’s adaptation, the harm of heat wave was more serious in early summer than in mid and late summer, but the duration of the heat wave had little impact on the excess mortality rate. Because of the habitants’ job need and outside time period selection, the damage of hourly high temperature in summer on human body had double peaks, appearing from 9:00 to 11:00 and from 19:00 to 21:00. The harm of high temperature and heat wave on human body presented a cubic function with age, being larger for the people aged 0-5 and 60-80 years. These results could be used as a reference for managing human health risk.