We selected four forest types, comprising of Cunninghamia lanceolata plantation (CL), Pinus massoniana-Lithocarpus glaber coniferous-broad leaved mixed forest (PM-LG), Choerospondias axillaris deciduous broad leaved forest (CA) and Lithocarpus glaber-Cyclobalanopsis glauca evergreen broad-leaved forest (LG-CG) in Changsha County, Hunan Province, in a mid-subtropical hilly region of China. Five permanent plots (20 m×20 m) were randomly established in each forest type. Soil samples (0-30 cm) were collected and divided into two layers (0-15 and 15-30 cm). Soil microbial biomass carbon (B_C), nitrogen (B_N), phosphorus (B_P) and activity of Invertase (INV), urease (URE), acid phosphatase (ACP), catalase (CAT) were measured, and variations of soil microbial biomass and enzyme activity and the relationship between soil microbial biomass, enzyme activity and chemical properties were studied. The results showed:(1) soil B_C, B_N and B_P, ACP activities were in the order as follows:CA > LG-CG > PM-LG > CL, both INV and URE activities were in the order as follows:LG-CG > PM-LG > CA > CL, and CAT activity ranked in the order of CA > PM-LG > LG-CG > CL, indicating that forest vegetation restoration had a significant promoting impact on the soil microbial biomass and enzyme activity. Path analysis showed that the direct and main influencing factors for B_C were SOC and TN/TP, for B_N were TN and TN/TP, and for B_P were TP and SOC/TP. However, TN/TP had a strong negative effect on B_C, and TN had a strong negative effect on B_N. The direct influencing factors for both INV and ACP activities were TN and TN/TP, of which TN/TP showed a strong negative effect on both INV and ACP activities. The direct influencing factors for URE were B_P/TP and B_P, of which B_P showed a strong negative effect on URE activities, and those for CAT were B_C/SOC and SOC, and also both had major positive effect on CAT. Furthermore, the residual path cofficients of soil B_C, B_N, B_P, in addition to INV, URE, ACP, CAT activity were small, impying soil chemical properties had a great influence on soil microbial biomass, and soil chemical properties and microbial biomass had a great influence on soil enzyme activity. Significant positive correlations were found between B_C, B_N and B_P, and between soil microbial biomass and soil enzyme activity.