Using the NCEP/NCAR reanalysis data and observation data, the variation of the heat wave frequency over China in summer during 1960-2015 is investigated. It is found that the most frequent heat wave in China is located in southeastern China and Xinjiang. Through the empirical orthogonal function analysis, the dominant modes of heat wave frequency over the above two regions are further analyzed. Examination on the atmospheric circulation anomaly and the sea surface temperature in the previous season shows that prevalence of the heat wave over southeastern China is attributed to the warming in Indian Ocean during previous months. The heat wave over Xinjiang is mainly due to the strong midlatitude warming over Pacific, Black Sea and Caspian Sea.