Abstract: Manglietia hainanensis Dandy is a fine native timber species used for reforestation in Hainan Island.In this paper,the biomass and its prediction models,biomass distribution among different diameter classes and components,and main nutrient allocation of 30 years old M. hainanensis plantation were studied.The result indicated that thd biomass regression equations of leaf, branch,trunk, bark,total above ground against D2H were better than that of against D;the total biomass was 144.066 t/hm2,among which aboveground biomass was 89.935 t/hm2;the tree layer and undergrowth biomass accounting for 78.81% and 21.19% of total biomass respectively;among the tree layer,biomass of bole,leaf,branch,bark and root were 54.127%,2.354%,7.762%,9.370% and 26.388% of the total respectively;excepting Ca,nutrient concentrations of N,P,K,Mg in leaf were higher than that in the other tree components(branch,bark,bole and root);the total nutrient of N,P,K,Ca,Mg stored in plant bodies of 30 years old M. hainanensis plantation ecosystem were 557.754,24.330,599.908,275.557,64.103 kg/hm2,quantity arranged from small to large of nutrient storage in different tree components was leafbranchbarktrunkroot.