The use efficiencies of microbial elements play an important role in regulating mineralization processes of soil carbon (C) and nitrogen (N), however, the transformation proportion of soil microbial to soil organic C (SOC) and N has not been adequately studied. In this study, we measured SOC, soil total nitrogen (TN), soil microbial biomass carbon (MBC) and nitrogen (MBN), soil C and N acquisition enzyme activity and soil microbial community structure in rhizosphere soil in 5–year–old, 9–year–old, 19–year–old, 29–year–old, and 35–year–old Pinus massoniana Lamb. stands in Thousand–island Lake forest farm., and elucidated the relationships between the microbial community structure and the soil microbial carbon utilization efficiency (CUE) and nitrogen utilization efficiency (NUE), as well as the threshold elemental ratio (TER). The results showed that SOC and TN in rhizosphere soil of 5–year–old P. massoniana stand were significantly higher than other stands (P<0.05), and its soil microbial C/N ratio was significantly lower than that of other stands (except for 9–year–old) (P<0.05), confirming that the microbial CUE was less sensitive to the substrate nutrient status. Microbial NUE in rhizosphere soil of 35–year–old P. massoniana stand was significantly higher than that of other stands (except for 19–year–old), indicating that most of the TN was transferred to MBN. This was consistent with the result that there was a significantly higher soil microbial biomass in 35–year–old P. massoniana than in other stands. The microbial NUE and TER in soil rhizosphere were significantly positively correlated with total soil microbial biomass and its component biomass (P<0.05), indicating that soil microbial reproduction is influenced by microbial NUE. In this study, the TER were greater than the soil C/N ratio in all P. massoniana stands, indicating that the ecosystem in the study area was C or energy-limited instead of N–limited. This result confirmed the fact that if the soil C/N ratio is lower TER, the cost of C acquisition in soil organic matter would be higher than that for N acquisition. The microbial CUE and TER in 5–year–old P. massoniana stand soils in this study were the lowest, and there was no relation with each other; implying that a compensatory relationship probably exists between CUE and NUE in young P. massoniana stands. This study highlights the importance of microbial element use efficiency and microbial communities in soil C and N cycling processes in rhizosphere, which provides reference for soil management in subtropical forest ecosystems.