This study was carried out to classify vegetation structure of the Anseong district in the Deogyusan National Park from May 2007 to September 2008 using the gradient analyses and phytosociological method. The vegetation communities were classified into Quercus mongolica, Carpinus laxiflara, Q. serrata, Fraxinus mandshurica, Betula davurica, B. costata, Pinus densiflora and Abies koreana. Characteristics of the vegetation such as species composition, layer structure, vegetation ratio, and the distribution of individual trees by DBH were significantly different among communities. The order of important value of the forest community with DBH 2cm above plants was Q. mongolica (40.02), C. laxiflora (25.65), Q. serrata (24.68), F. mandshurica (21.66), P. densiflora (19.12), Acer pseudosieboldianum (16.96), C. cordata (11.87), B. davurica (11.66), B. costata (10.90), Styrax obassia (10.90) and A. koreana (10.41). Distribution of DBH P. densiflora had a formality distribution, suggesting a continuous domination of these species over the other species for the time being. In contrast, F. mandshurica appeared limited to the valley of the sheet and a higher frequency of young individuals, suggesting a continuous domination of these species the development of a climax forest terrain. This study showed the correlation between each community and the environment according to DCCA ordination. The A. koreana community predominated on the northern slope of the park in the high elevation habitats which had many O-M. F. mandshurica community predominated in the highest elevation habitats which had many Moisture, EX-Cation and T-N. The P. densiflora community mainly occurred on the southern slope of the park in the low elevation habitats which had few Moisture, O-M and T-N. The Q. serrata community and C. laxifiora community appeared on the park in the middle habitats.