Urban heat island is a necessary issue in urban planning. However, there lacks a good way to study the heat island at the view of planning. This paper tries to combine Remote Sensing technology to establish an urban planning approach, which can study community scale of urban heat island and provide scientific way of heat environment study for urban planners. Tsinghua University is used as a case study to do the analyzing of heat environment using the approach mentioned above. It can be seen various surfaces have different contributions to the heat island in the campus and should be arranged premeditatedly. Therefore, the research of heat island is necessary for urban planning and a good planning project can reduce the heat island.