The index species diversity was used to discussing the stand or fall of intermediate cutting intensity. The result showed that, the number of the family, the genus, and the species of undergrowth vegetation species increased with thinning increasing. Species diversity, evenness index and richness index increased as well. There were some changes in the life-form spectrum and of plant community of Pinus tabulaeformis. The results also showed that the density o1" plant community of half mature P. tabulaeformis needed be further tended and thinned. The density should be controlled below 1 900-2 200 tree/hm2.