Abstract: The species composition and diversity of communities dominated by endemic species Cinnamomum japonicum var. chenii, Neolitsea sericea and Ilex integra in Zhoushan Archipelago were studied based on the investigation of typical plots. A total of 125 species of vascular plants, belonging to 62 families and 100 genera in seven plant communities were recorded. Among them, 16 endemic species to oceanfront belonging to 12 families and 14 genera were observed. The geographical elements were various, while tropical elements outweithed the temperate and subtropical elements. The dominant species were obvious in each layer. Species were dominated by Machilus thunbergii, C. japonicum var. chenii, I. integra and N. sericea in arborous layer, and by M. thunbergii and C. japonicum var. chenii in regeneration layer. The dominant species in shrub layer, herb layer and liana layer depended on community type and the environment. There was a large fluctuation of species richness (R), Shannon index (H) and Pielou index (J) between different layers of plant communities, which was related to the successional stage of community, the size of island, the distance from island to land, and human disturbance. The R and H indexes showed a consistent pattern of change trend. The R and H indexes in each layer of typical C. japonicum var. chenii community in Zhoushan were lower than those of other communities.