Abstract: Forest management plays an important role in soil carbon sequestration and global climate change mitigation. Soils were collected to determine the total organic carbon (SOC) and labile organic carbon under the low-efficiency Pinus massoniana forest (CK) and the improved forests, including clear cut and reforestation (QKCZ), closing for afforestation (FSYL), and replanting and mixed plantation (BZHJ). The results showed that SOC, microbial biomass carbon (MBC), dissolved organic carbon (DOC) and easily oxidizable carbon (EOC) significantly increased by 1.06 3.3 g·kg-1, 16.81 142.29 mg·kg-1, 12.83 43.71 mg·kg-1 and 0.16 0.54 g·kg-1 under the improved forests (including QKCZ, FSYL and BZHJ) respectively as compared with the CK. The MBC/SOC ranked as FSYL > CK > QKCZ > BZHJ, the EOC/SOC ranked as CK > BZHJ >FSYL >QKCZ, and DOC/SOC ranked as BZHJ > CK >FSYL >QKCZ. The results suggest that QKCZ is the best measure for low-efficiency Pinus massoniana forest improvement to increase carbon stability and sequestration in soil. Therefore, selecting suitable measure for low-efficiency Pinus massoniana forest improvement is an important measure to enhance soil carbon sequestration.