Abstract:The experimental plots in representative areas of the Shennongjia Nature Reserve were established.The forest communities in Shennongjia were investigated by using TWINSPAN. The plant communities in these plots were investigated to discern the pattern of species diversity distribution along the altitudinal gradient.The α-diversity and β-diversity were calculated by using the data collected.The α-diversity of the tree layer peaked in the evergreen broadleaved forest zone at low-elevation,the α-diversity of the shrub layer increased gradually at first and then decreased along the altitudinal gradient,while the α-diversity of the herb layer peaked in mid-altitude.The β-diversity peaked at mid-elevations where the composition of edificatory species changed.The transition zone was characterized by relatively high levels of species diversity and species turn-over rate.The overall species richness peaked in mid-altitude.The results of this research could provide a sound basis for reserve management and planning, as well as preservation of Sichuan snub-nosed monkey in this reserve.