Abstract: 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), Srensen index (C_s) 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 Eupatorium odoratum, Cyrtococcum patens, Paspalum conjugatum and Urena lobata. The S, H and D values of rubber plantations were the highest in Xishuangbanna, and the lowest in Honghe. The H and D values of the 8-10 years old rubber plantation were the lowest. The S, H and D values at altitude 500 to 700 m were the highest. The S, H and D values on slope greater than 25° were obviously higher than those on slope between 2° to 15°. A certain similarity of species composition existed among Honghe, Xishuangbanna, Puer, Lincang and Dehong, of which the C_s between Lincang and Puer was 0.47, being the highest. Temperature, precipitation, altitude and other four influencing factors together explained only 20.23% of total variation of dominantspecies distribution.

Key words: pomegranate, emery analysis, sustainable development, desertification control, Yunnan Province