Based on the survey data of 1 hm² deciduous and evergreen broadleaved forest plot in Tianmu Mountain of Zhejiang Province, we assessed species biodiversity by K-means clustering method, the individuals with diameter at breast height(DBH) ≥ 1 cm was divided into different forest layers according to tree height, and the features of species diversity in each layer were computed, compared, and contrasted. In addition, the direct and indirect biodiversity impacts also evaluated by using path analysis, namely, the quantity of decision coefficients. The objective of the study was to reveal the influence of vertical structure on community species diversity in an evergreen deciduous broad-leaved forest community. The results demonstrated that:(1) the forest community had multiple-layered vertical structure, which could be divided into five layers:shrub layer (1.4-4.2 m), sub-canopy layer (4.3-7.6 m), lower canopy layer (7.7-13.4 m), middle canopy layer (13.5-21.5 m), and upper canopy layer (21.6-36.5 m). (2)The species richness,abundance,the number of endemic species, Shannon-Weiner index and Simpson index of the community appeared a downward trend from bottom to top layers. (3)Shrub layer was the largest contributors to the community overall species diversity index and was much higher than the other four forest layers. And the decision coefficient of shrub layer towards overall species diversity of community that Shannon-Wiener index, Pielou index and Simpson index was 0.850, 0.651, and 0.775, respectively. (4) The density of lower canopy, middle canopy, upper canopy had a negative impact on the species number of the shrub layer. The larger density of the forest canopy was, the less the number of species would become in the shrub community as well as the complexity. In addition, the occasional and rare species in the shrub layer also played a key role in maintaining the species diversity of the shrub layer. In conclusion, the vertical structure of the community was critical in maintaining the overall species diversity of the given forest community. The shrub layer played a decisive role in the composition of overall species diversity, besides the number of occasional and rare species also played a key role on the composition, thus, species diversity of the community.