Abstract: In view of the shortcoming existed in the 3D-visualization method of mining subsidence without considering the 3D-terrain features in mining areas, CASS is utilized to extract the original terrain data of mining area, which realized the gross error elimination and interpolation of terrain data in CASS, developed mining subsidence forecasting system, and implemented the combination with GIS software, formed a loose type of integrated system including CASS, subsidence forecasting system, GIS software. The system can be used to implement a series of functions including data acquisition, preprocessing, subsidence 3D-forecasting, visual forecasting update of subsidence surface and spatial analysis, and it can overcome the shortage of the traditional forecasting system of mining subsidence which can't present the surface condition of subsidence surface in the mining area, greatly improves the efficiency and expressing effect of mining subsidence forecasting.