Urbanization increases the urban heat island effect for its intensity, horizontal and vertical sizes. When water vapor increases, it is expected that the water vapor feedback will be strengthened, and the heat island strength will be strengthened. In other words, the value of UHI Intensity will increase. From the experiment, we confirmed that when the amount of steam was increased, the UHI Intensity value increased, and when the amount was decreased, the value decreased. This proved our hypothesis that increasing water vapor increases the strength of urban heat islands.