The main objectives of this study are to investigate the most violently developed watershed of FungSan at the north of Taiwan and to build the giant hill slope land change detection models by using 1988, 1992, 1994, 1996, and 1998 SPOT images; digital terrain models; geographic information system coverages; photo maps; air photos; and sedimentation. The techniques of image processing software, IMAGINE and ARC/INFO, are to manage, analyze, demonstrate, and establish the GIS database. Using remote sensing and DTMs to establish the surface detection and the cubic detection models we can correctly realize the changing conditions of land use. The results are as follow: 1. Surface Detection Golf courses, the second freeway, LuFu Village Resort, and the mine area were developed within the last six years. The total developed area is 1,016 hectares, which is 4.87 percent of total watershed area (20806 ha). 2. Cubic Detection Through DTM overlay analysis we found the biggest depth dug is 71.9 meters and the filled height is 104.6 meters. The accumulation of the total depth is 32,008.1 meters. The total volume dug is 51,210,000 cubic meters. The accumulation of the total height is 30,060.6 meters. The total filled volume is 48,090,000 cubic meters. The result of all developed area soil loss would be 3,120,000 cubic meters. 3. Hydraulic Detection We still can't completely describe the changes of the rainfall or runoff in this developed watershed. Nevertheless, the result of the sedimentation of hydraulic detection has obviously increased.