Abstract: This paper deals with locals and vertical distribution of common plant species in four main tropical montane rain forestes in Hainan Island.The results showed that although each forest area contained certain same dominant or fundamental species on species composition in those forests distribution in the east,middle and west of Hainan,distinctive differences of species composition also existed in the every forest regions.The ecological factor differences in each forest area lead to distribution differences in vertical distribution of species with different ecological amplitude.Since temperature,humidity,wind,topography,and soil varied with the different altitude,the distribution of various ecological amplitude species diverged in the ecological factor effect.The species with narrower ecological amplitude distributed only in limited area.For example,the temperature sensitive species of tropical floristic composition located just in mountain valley because of the ecological influence.Some pure subtropical species only distributed in tropical hill or sub alpine area.However,the species with wider ecological amplitude or adaptation located from low to high altitude and from valley to mountain ridge.