Abstract: The biomass distribution of tropical mountain rain forest (sampling plot area 1500m2, clear-cutting) in Limushan,Hainan Island is studied. The result indicated that the total biomass above ground was larger than the average value of the tropical area in the world. The total biomass is 507.242t/ha, among which the tree layer biomass was 492.65t/ha, lower alyer wood and grass. 13.94t/ha, woody liana 0.67t/ha, epiphyte 0.06t/ha and parastic plants 0.15t/ha. The LAI value is as high as 9.572. By the analysis of tree biomass distributing in each DBH class and sub-layer, the authors found that the forest might be disturbed 300 years ago, and this indicated the tropical forest need very long time to recover the climax state after disturbance. In order to estimate the biomass of the similar forest communities, 8 regressive models had been proposed. The models included the whole tree biomass (above ground), the trunk, bark, branch leaf, plank-but-tress, woody liana biomass and the leaf area.