The activities of soil urease, sucrase, neutral phosphatase and catalase in different soil layers, vegetation community and land use in the Yunwu Mountain area are studied. The result shows that: the activities of soil sucrase, urease, neutral phosphatase and catalase are all higher in the upper layer of the profile and decrease with the depth. Under the enclosed condition, four different enzymatic activities in surface layer soil(0—20cm) is greater than sub-layer(20—40cm). The activities of soil urease, sucrase, neutral phosphatase are Stipa gradiss.+Stipa bungana Community Artemisia sacrorum community Stipa bungana community Thymus mongolicus community in the surface layer(0-20cm). The activity of soil catalase is Artemisia sacrorum community Stipa gradiss. + Stipa bungana Community Stipa bungana community Thymus mongolicus community. Under the two different land use of Stipa bungana community, the activity of soil urease shows that the farmland is greater than enclosed land, but the activity of soil sucrase is enclosed land greater than farmland. There is no obviously soil erosion and no the enzymatic activity difference between the farmland and the enclosed land in the study area. So it also shows the correct land use can prohibit the soil degradation.