Abstract: With the development of society,Three-dimensional information of man-made buildings is being used in many fields,therefore,the automatic extraction of buildings is a research focus.DSM(digital surface models) can be generated in quasi-real-time by airborne three-dimensional imager.In this paper,we focus on the building extraction and edge regulation.First the DSM image is segmented and we can get the rough contour of buildings,and then the edges of buildings are regulated because the shape of the buildings is usually regular.The height of building is also calculated according to the DSM data.So,the three-dimensional information of building can be given automatically.The method discussed in the paper is used in a test area,and the result is satisfactory.