The aims of this study were 1) to classify forest vegetation effectively by Landsat Thematic Mapper data, and 2) to apply some transform models of Digital Terrain Model (DTM) for analyzing forest distribution characteristics on topographic and topoclimation changes in mountainous region. The research area was Gumo-son Provincial Park, near Gumi city, Kyungsangbuk-do. The results are summarized as follows. 1. To classify forest and land cover types, unsupervised classification method was used. Relative radiation indexes for every pixels were calculated to remove the effects of shadows. Six forest and non-forest classes, that is, coniferous, hardwood., mixed forest, reservoir, bare land, and other undetectible areas were seperated with over 80 percent accuracies. 2. The portion of mixed forests in Gumo-son area was 17%. This is much less than the ratio of 39.9% from interpretation of aerial B; W infrared photographs. On the other hand, the ratios of coniferous and hardwood were revealed to be 45.3% and 28%, respectively. The areas of these two types were greater as much as 1.7 and 1.4 times respectively than those areas from aerial photographs. These variations are thought from the differences of pixel size and unit area of interpretation adapted to both methods. 3. DTM was very suitable means to memory, retrieve, and convert land surface informations. In this study aspect, slope degree, solar radiation index, and drainage accumulation value were derived from the DTM, and it was revealed that elevation, aspect, drainage accumulation value were effective to explain forest type distribution. 4. Landsat TM data is good source of land-related informations with its timely, periodic, and spectral properties. DTM has also spatial informations on earth surfaces in digital forms. The values of these two sources are accelerated when used together or supplementary in such cases of analyzing and modeling forestry, the extents of utilizing these informations are expected to grow and improve much higher.