This study was carried out to analyze forest vegetation in Seodaesan of Geumsan, Chungnam Province. Employing the releve method of Braun-Blanquet and quadrat method, 36 plots were sampled in forest of Seodaesan. The sub-communities were classified into Pinus densiflora, Acer pseudosieboldianum, and Carpinus laxiflora sub-community of Quercus mongolica community. The importance values were 77.07 in Quercus mongolica, 40.79 in Pinus densiflora, 17.03 Fraxinus rhynchophylla, 14.06 in Fraxinus sieboldiana, 13.99 in Quercus serrata, 12.93 Acer pseudosiebotdianum. Coverage rate was 84.6% in tree layer, 52.8% in subtree layer, 29.1% in shrub layer, 27.9% in herb layer, respectively. Most of the DBH of Quercus mongolica and Pinus densiflora was between 5cm and 20cm. Therefore, Quercus mongolica and Pinus densiflora might be dominant species in the study area for several decades. Acer pseudosieboldianum and Carpinus laxiflora sub-communities were distributed mainly in a high-altitude and northern and north-western area. Pinus densiflora sub-community was distributed mainly in a low-altitude and western area.