To accurately calculate carbon fixation capacity of P.pubescens forest in Hunan Province and promote the balanced and stable development of P.pubescens forestry in Hunan Province,standard sample plot was set in major producing area of P.pubescens in Hunan Province,and biomass of 258 P.pubescens was measured according to DBH and age class.Multivariate regression method was used to establish univariate (DBH as independent variable) and bivariate (DBH and age class as independent variables) models of total aboveground biomass and organ biomass of P.pubescens .Model evaluation and test showed that each model accorded with the applicable precision and had the appropriate prediction level.