Chodo Archipelago ($125^{circ}$45 $-126^{circ}$13 E and $34^{circ}$15 $-34^{circ}$25 N, ca. $56.7km^2$), a part of the Dadohae National Marine Park, largely is covered with substitutional vegetation under various human impact such as grazing, cutting for firewood. However natural vegetation is partially distributed in the tutelary shrine forests, deep valleys and etc. From October 1988 to June 1989, phytosociological investigation of this forest vegetation was carried out by Braun-Blanquet s method. The forest vegetation was classified into 1 association and 7 communities. Ardisio-Castanopsietum sieboldii, Machilus thunbergii, Quercus acuta, Litsea japonca, Eurya japonica-Pinus thunbergii mixed forest, Pinus densiflora, Pinus rigida afforestation. Carpinus coreana community. Based on the classification, the actual vegetation map was drawn in 1 : 50,000 scale.