This study was carried out to analyze Pinus densiflora forest in islets of southwestern coast of the Korean peninsula by the phytosociological methods. As a result of the investigation of 26 quadrats, the pine forest was classified two communities and six subcommunities : Ardisia japonica-Pinus densiflora community and Isodon japonicus-Pinus densiflora community, and Farfugium japonicum subcommunity, Quercus serrata subcommunity, Typical subcommunity of Ardisia japonica-P. densiflora community, Juniperus rigida subcommunity, Pourthiaea villosa subcommunity and Typical subcommunity of Isodon japonicus-P. densiflora community. The subsidiary knowledges from this study provide practical information to clarify the syntaxonomy of natural pine forest of the Korean peninsula by the phytosociological methods.