Forest vegetation of Geochilbong (1,177 m) in Deogyusan National Park is classified into mountain forest vegetation and flatland forest vegetation. Mountain forest vegetation is subdivided into deciduous broad-leaved forest, valley forest, coniferous forest, afforestation and etc., while riparian forest was found under the category of flatland forest vegetation. Including 89 communities of mountain forest vegetation and 4 communities of other vegetation, the total of 93 communities were researched; the distributed colonies classified by physiognomy classification are 32 communities deciduous broadleaved forest, 21 communities of valley forest, 12 communities of coniferous forests, 24 afforestation and 4 other communities. As for the distribution rate for surveyed main communities, Quercus mongolica, Quercus serrata, Quercus variabilis communities account for 56.54 percent of deciduous broad-leaved forest, Fraxinus mandshurica, Cornus controversa community takes up 46.58 percent of mountain valley forest, Pinus densiflora community holds 74.98 percent of mountain coniferous forest holds. In conclusion, minority species consisting of Quercus mongolica, Quercus serrata, Quercus variabilis, Fraxinus mandshurica, Cornus controversa, Pinus densiflora are distributed as dominant species of the uppermost part in a forest vegetation of Geochilbong in Deogyusan National Park. In addition, because of vegetation succession and climate factors, numerous colonies formed by the two species are expected to be replaced by Quercus mongolica, Carpinus laxiflora and Fraxinus mandshurica which are climax species in the area. However, the distribution rate of deciduous broad-leaved forest seems to increase gradually due to global warming and artificial disturbance.