Abstract: The drawbacks of the traditional method of delineating surface movement were described in this paper. Take an iron for example, firstly, we preliminary delineate surface movement with traditional method. Then, the scope of surface movement with FLAC^3D was imitated. Combining practical geological conditions and the imitative result as quantificational reference for comparison and analysis, the surface movement was revised. Finally, the scope of surface movement was delineated scientifically.