Abstract: In this paper,studies were made of the total biomass,organ biomass of main trees and diversity of tree layer,shrub layer and grass layer from different density adjusting modes (4 950 trees per hectare,1 800 trees per hectare and 1 160 trees per hectare),and analysis was made of effects of density adjusting on biomass and biodiversity of artificial Picea asperata forest through representative sampling and modeling.The result showed that both individual biomass and stand biomass that mainly came from tree biomass increased significantly after density adjusting 6 years later.There were more stand biomass with 1 160 tree per hectare than those with other density.Meanwhile,density adjusting promoted significantly trunk biomass proportion.Finally,density adjusting increased the diversity of shrub and grass under forest significantly.