Abstract: With 10 common species of understory shrub in three natural forest types，including SpruceFir Mixed forests, PolarBirch secondary forests and Larch plantation in Jinggouling Plantation Changbai Mountains as test objects, crown area(Ac),project volume(Vc), square ground diameter by height(D2H) were used as variables in component biomass models. According to the growth forms, treelike(single trunked) mixed models and shrublike(multistemmed or low branching) mixed models were built. The shrub biomass along with its distribution in different species and components were investigated using the bestfit models which were judged by high R2 and low SEE. The results showed that the bestfit speciesspecific component model forms were linear, quadratic or cubic equations, the variables in stem and branch models were D2H or Vc, and in leaf models were Ac or Vc ,while in root models were D2H. The bestfit mixed model forms were power or cubic equation, the variables in these models were D2H while the branch of mixed model of shurblike plants was Vc .The biomass of understory shrub in natural SpruceFir Mixed forests, PolarBirch secondary forests and Larch plantation was 4 013.59,3 950.66 and 4 649.36 kg/hm2 respectively, and treelike plants make more biomass contribution than shrublike plants.