Abstract: Based on a field investigation of 40 vegetation plots (30 m×30 m) in Kunyu Mountain and the main site factors, forest communities were classified and the species diversity pattern along the altitudinal gradient was analyzed by using two-way indicator species analysis (TWINSPAN), detrended correspondence analysis (DCA), and canonical correspondence analysis (CCA). Analysis of species accumulation curves indicated that samples from the 40 permanent plots were statistically sufficient for analyzing the species composition. The results showed that the forest communities were classified into 9 types by TWINSPAN. The results of DCA clearly reflected the distribution range of various community types, and CCA indicated the influences of site factors on the distribution pattern of community types and species. Species richness increased sharply with an increasing elevation below 300 m, with the maximum at 300 m, then decreased significantly, and did not change greatly above 450 m. Shannon-Wiener index rose slightly with an increasing elevation, and Simpson index had a similar trend. Pielou’s index increased gradually below 500 m, and rose sharply above 500 m.

Key words: Kunyu Mountain, forest community, species accumulation curves, TWINSPAN, DCA, CCA, species diversity, elevation gradient