Abstract: In July 2018 , Castanopsis carlesii forest at Dayin Mountain, Quzhou of Zhejiang province was divided in to 10 sample plots with same area, and investigation was conducted on species composition of communities. The result showed that there were 117 plant species, including 24 species of tree, 75 species of shrub and 18 species of herb. Castanopsis carlesii, Elaeocarpus decipiens and Ilex formosana were the dominant tree populations with large niche width. The niche similarity ratio and niche overlap between Castanopsis carlesii and Ilex formosana populations were the highest. In order to provide a theoretical basis for the protection of Castanopsis carlesii forest community in Dayin Mountain, this study discussed the utilization status of surrounding environmental resources and the effects of their interrelations on the main plant communities.