Based on the plant species survey data of 49 plots( 10 m×10 m) in the rubber plantations in Yunnan Province,species composition and diversity,coefficient of similarity and environmental factors of understory plants were analyzed by using the species richness( S),Shannon index( H),Simpson index( D),Srensen index( Cs) and RDA ordination in this paper. The results showed that there were 387 vascular plant species,belonging to 102 families and 274 genera in the rubber plantations. The most common species were ...