With the acceleration of urbanization,our cities become hotter and hotter.A good control on the heat environment of buildings is useful to improve people's living standard.Considering the phenomenon of "urban heat island",this paper analyzed the influence of a building on other buildings and its surrounding environment due to its form,allocation and thermal character of building materials from the angle of heat reflection,and brought up a proposal to resolve this problem.It opens a new way to improve the thermal environment of a city.