Abstract:The characteristics of species diversity of Carpinus pubescens community and its successional community on the karst mountains in an area of 1 600 m~2 in Guiyang, Guizhou Province, were analysed using the formulas of Simpson's and Shannon-Weiner's indices, and evenness. The individual number, plant height and breast height diameter (DBH) of all trees higher than 2.5 cm in DBH were measured. The two indices were further estimated by the jackknife procedure. The results showed that Simpson's index of the community ranged from 1.14 to 3.88，Shannon-Weiner’S index from 0.50 to 2.43, and evenness from 0.19 to 0.71. With the development and succession of the community．the species diversity showed a trend of high→low→high．The jackknifing estimation value of Simpson’s index of the community ranged from 1.14 to 3.88, and its estimation interval from 1.O4 to 5.10，while of Shannon-Weiner's index ranged from 0.52 to 2.58．and its estimation interval from 0.24 to 3.14. The jackknife method is suggested to be a more effective too1 for estimating the index of species diversity．