Abstract:Based on the survey of 3 to 5 sampling plots with areas of 1 300-3 000 m2 in communities at four sites of tropical montane rain forest at 700-1 300 m altitude On Hainan Island， the spatial feature
ofspecies diversity in each layer of the community was studied．The species diversity of tree and herb layers decreased in communities located from east to west, i.e. from Diaoluo Mountain to Wuzhi Mountain，Bawangling，and Jian fengling,while that of shrub layer and extrastratum plants increased．Spatial fluctuation of species diversity in extrastratum plants and tree layer were more stable than in shrub and herb layers．species diversity in tree，shrub，extrastratum and herb layers of the montane rain forest communities had various trends at altitudinal gradient．The species diversity in tree，shrub, extrastratum and herb layers within a community showed different features according to slope aspect．