The elevational distribution pattern of biodiversity is always a hot topic for ecological research. As a Comprehensive factor, the elevation drives the spatial distribution for species composition, phylogeny and functional diversity of plant communities. Taking the forest plant communities ranging from 900 m to 1600 m on the south slope of Daiyun Mountain as the study object, we analyzed the relationship between species diversity and phylogenetic diversity. Then we explored the environmental driving factors for species diversity and phylogenetic indices. Thus we studied the significance effect of environmental factors on the community assembly and biodiversity maintenance. The results showed that: (1) The phylogenetic diversity and species diversity indicated an intermediate high expansion pattern along the elevations. (2) The species diversity Margalef index and Shannon-Wiener index were significantly positively correlated with phylogenetic diversity index, indicating that the higher species diversity is, the higher the phylogenetic diversity is. The Shannon-Wiener index was significantly correlated with species diversity indices (Margalef, Pielou, Simpson index), phylogenetic diversity and structure, and could replace other indices to some extent. The Pielou index, Simpson index and Shannon-Wiener index were significantly positively correlated with the net relatedness index (NRI) and net nearest taxa index (NTI), indicated that the community dominance and evenness were strongly correlated with the phylogenetic structure. (3) Soil total phosphorus content was the main driving factor affecting phylogenetic diversity and species diversity. Soil water content was the most significant factor affecting Shannon-Wiener, Pielou and Simpson indices. The elevation was the main influencing factor affecting phylogenetic structure. Elevation and soil factors jointly drove the species diversity and phylogenetic diversity of forest communities in the south slope of Daiyun Mountain, and thus further verified the high correlation between species diversity and phylogenetic diversity. The results could provide a theoretical basis to reveal the spatial distribution of forest community.