Abstract Species diversity in total, in the arbor layer, the shrub layer, and the herb layer was studied in artificial spruce (Picea asperata) forests at different ages (10-70 years), secondary birch forests and primitive fir (Abies faxoniana) forest. Several diversity indices were selected for use, which were the Margalef index, Simpson index, McIntosh index, Shannon-Wiener index, Pielou’s even index, Hurlbert’s even index, the number of species and individuals, and the canopy coverage. l) The total species diversity of the artificial spruce forests increased with their age at the younger stages, and increased observably in the process of canopy closure, but decreased slightly in the following stages with some fluctuations. In the arbor layer, the trend was the same as the total. In the shrub layer, the species diversity of the artificial spruce forests decreased slightly with age in the younger stages, but increased observably after the closure of‘ canopy, then decreased slowly later. In the herb layer, the species diversity of the artificial spruce forests was very high at the early stages, but decreased with the process of canopy closure, increased slowly after the canopy closure, but then slowly decreased later. 2) The trend of the even indices was contrasted to the species diversity indices, and the range of fluctuation was small. 3) Among the primitive fir forest, the secondary birch forest and the artificial spruce forest of equal age, the number of species, Margalef index, Simpson index, McIntosh index and Shannon-Wiener index in total, in the arbor layer, in the herb layer of the primitive fir forest were the highest, but the even indices were the smallest; in contrast, the species richness, the Simpson index, MacIntosh index and Shannon-Wiener index in total, in the arbor layer, and in the herb layer of the artificial spruce forest were the lowest, but the even indices were the highest. 4) Dynamics of species diversity were closely related to the degree of canopy coverage of the communities. The species diversity declined with increasing canopy coverage. 5) Species diversity of the artificial spruce forest was not only less than in the secondary homochronous birch forest. And far less than that of the natural primitive forest, but was also lower about 70 years after restoration. And the coverage of the shrub layer and the herb layer was very low, which indicated low efficiency of water and soil conservation. It is necessary to adjust the structure of the artificial spruce forests to restore biodiversity and to enhance the ecological effect of these forests.