Abstract: Structural diversity of forests in Baihuashan Mountain, Beijing, was surveyed through plotless method combined with branch and leaf coverage estimation in different layers, and new structural indices were constructed, calculated and compared among different communities.On the basis of previous work, structural diversity of forest community in stand scale was described by vertical complexity index and horizontal heterogeneity index.In correlation analysis among the new indices and other common-used biodiversity indices, the new indices were closely related to tree height inequality index and Shannon-wiener index of tree and shrub layer, which indicated that the new indices were good at indicating structural diversity in different forests in Baihuashan Mountain.The results show that, in natural forests, structural diversity of pioneer community is much lower than that of late successive community;while in plantations, structural diversity is determined by the development stage and tree species, and tending would increase the horizontal heterogeneity and decrease the vertical complexity.