Heat waves are of the most important climatic disasters, which have devastating environmental implications in the nature every year In this study. In this study, non-parametric statistics of trend analysis of Sens were used to investigate the trend of 30-year frequency series (1970- 2018) of hot-wave events in both hot days and hot waves (hot days with a duration of 2 days or more). At all stations, there was an increasing trend both in the number of hot days in Tehran and in the frequency of warm-wave events at 5 stations in Tehran. The main objective of this study is to investigate the population exposed hyperthermia in Tehran during hot waves and based on the frequency analysis of the recorded hot waves, the wave was selected from July 20 to July 28, 2013. Using spatial statistics analysis of hot spots, critical regions of Kermanshah were identified during heat wave and the population of high risk was obtained from demographic using tabular matrix analysis. The results showed that hot critical cores significantly affected areas 6, 7, 8, 10, 11, 12, 14, 15, 4, 7, and 19 during hot-wave days. Has done the average temperature of this hot thermal core averaged more than 43 ° C during two warm waves. In this hot thermal core that significantly rises in temperature during the heat wave, there are a total of 2954485 people in Tehran, which is 35% of the population of Tehran. Also, in this core, there are 13,000 statistical blocks, which is 40% of the total population of Tehran.