Using remote sensing technique to the field of the City investigation on land and resources, ecologic environment and build planning is very necessary to adapt to the fast development of morden cities. By the end of Dec.1995, Chongqing has finished the remote sensing comprehensive study work. The data, image, picture and reports from the investigation are very important to the City development and harness of land and resources and the City management. It’s also useful to laying down the build planning. In this paper, the authors take Chongqing as an example, introduces the function of remote sensing technique and its application effect, in order to make this technique to be applied in wide field.