Abstract：The images before and after earthquake of Beichuan County are compared, based on tectonic background of regional geology, moreover, the various terrain factors including slope, aspect, Plan of curvature, profile curvature, slope rate and so on, are extracted from Digital Elevation Model (DEM),to quantitatively analyze the terrain information. The preliminary result indicates as follows: in Beichuan County, the slope ranges from 40° to 50°, slope change rate is between 18° and 30°, and relief amplitude ranges from 50 m to 70 m, the seismic secondary disasters,such as landslide and barrier lake triggered by landslide in some valley areas are extremely easy to occur in even wider areas.
