Abstract: By means of combining harvest method with the method of dimension analysis, this paper studies the biomass of Castanopsis orthacantha sprouted shrub community above the ground in Kunming region.The authors concen- trate on their study on the biomass of dominant species of the community above the ground, the law of biomass distribution of diameter class and organ, the gross biomass of this kind of communinty, and the law of gross biomass distribution of layer and specis.The results are as follows. 1.The biomass of a kind of community can be calculated by the same model when its age is close to each other, and its structure and species composition are similar. 2.The biomass of dominant species of Castanopsis orthacantha sprouted shrub community is 24.56t./ha..The law of diameter class distribution of it is as follows.The more the number of thin branches(1≤d2cm) is, the less its biomass is.The fewer the number of thick branches(d≥3cm) is, the more its biomass is and this occupies an absolute dominant position.The law of distribution of organ biomass is as follows.The proportion of biomass of leaves and wood gets smaller and smaller and the leaves'biomass tends to be a fixed weight, but the wood's biomass increases constantly. 3.The gross biomass of Castanopsis orthacantha sprouted shrub commu- nity is 31t./ha.and the law of distribution of layer biomass is as follows.The biomass of dominant layer or first shrub layer occupies a dominant position absoluty but the biomass of second shrub layer and herbaceous layer is very little.