Abstract: Based on the above-ground biomass data of Chinese fir (Cunninghamia lanceolata) and Masson Pine (Pinus massoniana) plantations in Guizhou Province, the generalized single-tree biomass equations suitable for different species and regions (central region and other region) were established using linear mixed model and dummy variable model methods, which provided effective approaches to simplify the biomass modeling. The results show that the above-ground biomass estimates of individual trees with the same diameter are different in some extent among different tree species and geographic regions, and linear mixed model with random parameters and dummy model with specific (local) parameters are better than population average model; and linear mixed model and dummy variable model approaches are almost same effective and may be applied to develop other generalized models such as tree volume equations.