Taiwan is an unstable area of a geological state. The mountain land slide area collapses frequently because typhoons pass this island at summer and autumn every year and human overuse land. The produced reasons of the mudflows and landslide are related with height, slope, aspect and geological state. To solve and prevent mudflows and landslide problem effectively, people must investigate the location of the slide land and the relation with other relevant factors. Using remote sensing at land monitorship and land use are very popular. The work of recognition will make people confuse because the slide land satellite's optical spectrum characteristic approach to river valley uncover place. To confirm the image of the satellite's classification effectively should use other message to assist. Lien-hua chi Experimental Forest is this paper's study area. This paper will use the 1999 SPOT images and the factors to recognize slide land. And then take land use map which scaled 1:25,000 to make sure the classification is correct. Use relevant information to conjecture the possible reason of collapsing change. It will provide related organization that the geological calamity area at typhoon season.