Abstract: ObjectiveUnderstory species composition and shrub-grass species diversity were analyzed in rubber plan-tations of Guangdong province,in order to provide references for construction of environment-friendly ecological rubber plantations. MethodUsing richness index,Shannon-Wiener index and Simpson index,understory plant species composition and shrub-grass species diversity were analyzed in rubber plantations of Guangdong province after survey of 30 sample plots (400 m2). ResultThere existed 211 vascular plant species belonging to 157 genera in 65 families in the rubber plantations. The most common species were Borreria latifolia,Cyrtococcum patens,Dicranopteris linearis and Microlepia speluncae. The shrub-grass species diversity of rubber plantations firstly increased and then decreased with the increase of slope in general, which was the richest on slope with 15°≤slope<25° and the worst on the flat. The diversity of rubber plantations generally increased with the increase of stand age and canopy density,but there was no significant difference (P>0.05,the same below). In addition,shrub-grass species diversity of rubber plantation in northern direction was the richest,but not significantly different from diversity of other aspects. ConclusionThe understory shrub-grass species di-versity is abundant in rubber plantations of Guangdong province. However,it is necessary to avoid some human disturbance as much as possible in the process of rubber forest management on the premise that doesn’t affect normal production,so as to better restore understory plant diversity and construct environment-friendly ecological rubber plantations.