It is an important aspect of studying hazard-affected body of geological hazards. Extracting surface feature automatically based on high-resolution remote sensing image will be an important way to distinguish hazard-affected body of geological hazards. On the basis of a method of object-oriented, the hazard-affected body object is formed in the high resolution remote sensing image which is segmented. The complete edge of hazard-affected body object is extracted from the hazard-affected body image which is processed by extracting gradient, binarization, removing spurs, and so on. The results indicate that the hazard-affected body edge is with reasonable completeness and accuracy. The method is of universal application and superior to the traditional methods.