Stand structure changes with forest age caused the variation of soil microenvironment, which can directly or indirectly affect soil microbial biomass carbon and nitrogen, and soil enzyme activities. To better understand the change characteristics of soil microbial biomass contents and enzyme activities along an age sequence of spruce plantations, this study was conducted to evaluate the theoretical basis for restoration and effective management of subalpine plantations. In this study, Picea asperata plantations of various ages (25, 40, 50, and 60 years old) were selected in Miyaluo forest area of western Sichuan, China. The soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), available nitrogen (AN) and pH, microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), dissolved organic carbon (DOC), dissolved organic nitrogen (DON) and light fraction organic carbon (LFOC), soil enzyme activity index(β-glucosidase, βG; Cellulose hydrolysis, CBH; β-N-acetylglucosaminidase, NAG; Phenol oxidase, PHO and Peroxidase, PEO) in 0-20 cm soil was measured,respectively. The results showed that the MBC and MBN increased up to 40 years, and then decreased with the increase of age. There was a similar trend in changes of the activities of βG, NAG and PHO, while βG and NAG were highest at 50 years, and PHO was highest at 40 years. PEO activity of 50 years was significantly lower than other plantations. The activity of CBH increased with the increasing age of Picea asperata plantation stands. Redundancy analysis (RDA) indicated that AN, pH and DOC were main influence factors of soil enzyme activities in the top-layer soil, accounted for 65.4%, 9.7% and 7.6% of total variation of soil enzyme activities, respectively. Overall, our results suggested that the growth of Picea asperata had a significant effect on soil microbial biomass and enzyme activities. The soil fertility in 60 years of Picea asperata plantation was the lowest in all Picea asperata plantations. Therefore, we can increase carbon and nitrogen elements (especially nitrogen) devotion to improve soil quality and enzyme activities in Picea asperata plantations nearly 60 years.