Abstract: Species diversity of plant communities in Longwang Mountain was studied by using seperately 2 index of richness index (R1, R2), diversity indices (D, H) and evenness index(J1, J2). The results showed that the deciduous broadleaved forest in this area had rich plant species. Among them, the number of shrub species were the most and the herb were the least. It totaled 54 families, 91genera and 140 species (including variations) of vascular plant species. The vertical structure of community was relatively beautifully layered which could be divided into tree layer, shrub layer, herb layer, and a definite number of interstratum plants besides. The dominant species in tree and herb layer were quite obvious, but the dominant species in the shrub layer of the differences was the opposite. The change trend of richness index（R1 and R2）、diversity index（D and H） and evenness index （J1 and J2） were the same （shrub layer>tree layer>herb layer）.Ttest results showed that the differences of the species richness and diversity between all layers were significantly. The evenness index between the shrub layer and the other layers has no significant difference, while the evenness index of the tree and shrub layer were relatively significant.