Abstract: The tropical rain forests dispersed over Hainan Island, southern China and those occurring in Xishuangbanna, southwestern China were comparatively studied. The main points of the study are as follows: 1.According to our statistics of the species percentage and importance value in community, the lowland rain forest and tropical monsoon forest on Hainan share the same dominant families with the tropical rain forest in Xishuangbanna, suggesting that the forests in the two regions are floristically common in nature.

Key words: Tropical rain forests