Abstract: The aboveground biomass of individuals with different growth potentials in natural Pinus densiflora forest with different stand densities was measured in Yanbian,Jilin Province.The variation of individual biomass affected by densities was in order of dominant tree<intermediate tree<suppressed tree,while the distribution proportion of biomass in different organs affected by densities was:in order of trunk>branch>needle>bark.The biomass components of P.densifliora with different growth potentials varied markedly with the approaching of density class Ⅲ,and the change of intermediate trees was similar to the whole stand.The vertical distributions of biomass of different trees were different from each other,but all showed that the biomass of trunks and barks was mainly distributed below 6 m high from ground,that of branches was within 6～10 m high,that of needles was uniform in the upper,middle and lower layers,and that of branches and needles in upper layer was least affected by density.