This summer, Korea had to deal with extreme heat wave. In this research, fruit flies (Drosophila) were used to analyze the behavior of insects at a high temperature. For the experiment, three male and female fruit flies were put in each of 4 media vials. One vial was incubated at 25°C, the average temperature in August. In three vials, fruit flies were incubated in each 28°C, 30°C, and 32°C for the experiment. The breeding coefficient and death rate were calculated by counting the number of imago fruit flies in each vial and how many of them died. Also, we observed various behavioral differences. The air speed velocity of fruit flies was measured to compare the difference in behavior of fruit flies. Finally, size of them were observed by dissecting microscope. From this research, we can realize the correlation between global warming and the ecosystem of insects.