The biomass structure of Bambusa wenchouensis population was studied in this paper. The regression models of each biomass component based on DBH and the diameter of culm base were constructed. The result showed that culm biomass of B. wenchouensis accounted for 73.1%, much higher than that of Phyllostachys edulis. DBH, diameter of culmbase and the different components of B. wenchouensis were highly corretated each other. The model of culm fresh weight (W1) and total fresh weight (W4) based on DBH (D) were W1=0. 370 3 D2.0922 and W4=0. 512 2 D2.0391 respectively. By using these models, the different biomass components of B. wenchouensis could be estimated in practice.