Abstract: Biomass allometry of Pterocarpus indicus seedlings under different fertilization was studied based on the multiple regression analysis and analysis of covariation(ANCOVA).Combined with residual analysis,the biomass estimation model was established.The effects of fertilization on biomass distribution were also analyzed based on the Duncan's multiple comparison.The result showed that: 1) there were no effects of the fertilization on the biomass allometry of Pterocarpus indicus seedlings,2) the biomass distributions were affected by the fertilization,3) there was inverse relationship between the leaf biomass distribution and the root biomass distribution,i.e.the biomass allocation to leaf increased while the biomass allocation to root reduced.