Abstract: In this paper,studies were made of the establishment of above-ground and below-ground singletree biomass equations of aspen. Firstly the work was done for establishing its total above-ground,stem wood,stem bark,branch,leaf independent biomass models and compatible models with the volume biomass. Then a system of aspen biomass models was established,in which the total above-ground biomass equations were compatible with stem wood,stem bark,branch,leaf biomass equations. Finally a root-shoot ratio model was established,which could be used to estimate below-ground biomass together with aboveground biomass equation. The results showed that all the models should be able to fulfill technical regulations and to be applied to the biomass estimation of aspen.