Abstract: Species diversity of the Yukeng forest communities in Xianju County of Zhejiang Province was determined and analyzed by using the index of species richness, species diversity and community evenness. The results are given below. The communities are mainly composed of evergreen tree species under favorable conditions. The species richness and species diversity index of the woody plants are obviously greater than those of the herbs. In terms of the community's vertical structure, the species richness and species diversity index of the second layer of the woody plants are much greater than those of the first layer. The third layer of the woody plants is the greatest in relation to species richness while the herb layer is the smallest. If the species diversity index and community evenness are concerned,the second layer of woody plants is the greatest while the herb layer the smallest. The diversity indices of various la yers of the woody plants and the herb layer are to a certain degree different among the plots.