Abstract:Triadica rotundifolia is a common species of secondary forest in limestone region. In order to understand the dynamic changes of T. rotundifolia community in limestone region, the species diversity and population structure of T. rotundifolia community in Qingxin and Yangshan Counties, Guangdong Province, were studied by plot method. The results showed that there were 140 vascular plants in two plots with a total area of 4800 m2, belonging to 65 families and 118 genera. The dominant families were Euphorbiaceae, Rubiaceae, Rutaceae, Moraceae and Oleaceae. Among them, the tropical distribution elements at genus level were dominate accounting for 79.6%, and then 18.3% for temperate distribution elements. The species richness, species diversity and evenness of T. rotundifolia community in Qingxin were higher than those in Yangshan, except for evenness of herbal layer. T. rotundifolia population in Qingxin is unstable owing to lack seedlings and small individuals, while T. rotundifolia population in Yangshan is young comparatively with abundant small trees. With succession of the community, the dominance of T. rotundifolia in community would be replaced by other shade-tolerant species.