The simulation and analysis of the Changsha urban thermal environment and the analysis of the infrared temperature map of Changsha urban area were presented. The results have shown that green land and water coverage have significant effects on alleviating the urban heat island effect and improving urban air quality. The results have also shown that the road layout of the city is really relevant to urban regional thermal environment, and the rational design of urban road layout may take the advantage of the prevailing wind for natural ventilation, and the layout of high-rise buildings should be coincident with the urban road direction to utilize the urban roads ventilation to improve the thermal environment.