Abstract: The paper provided a systematic analysis of ecological restoration effects of natural secondary forest of closure area in Chao Guanxi Gou, Miyun County. The study indicated that through nearly twenty years of hillclosing afforestation, canopy closure has been improved about 0 2; cover rate of forest has raised from 7.2% to 93.8%; biodiversity, tree biomass and vegetation community have increased to a great extent. Compared with the average canopy closure before hillclosing afforestation in this area, it has raised 0.1～0.2 and has been over 0.4. Forest coverage degree is over 90%. Consequently, the forest plays more important roles in intercepting precipitation, improving water storage capacity of soil, decreasing the surface runoff, controlling soil erosion.