Based on the long-term experiment in Ansai Soil and Water Conservation Experimental Station, Chinese Academy of Sciences, this study investigated the effects of five different fertilization methods, including no fertilization (CK), combined application of nitrogen and phosphorus (NP), combined application of nitrogen, phosphorus and potassium (NPK), single application of organic fertilizer (M) and combined application of nitrogen and phosphorus in organic fertilizer (MNP) on soil organic carbon (SOC) composition and carbon pool management index (CPMI). The results show that different fertilization treatments increase SOC contents and components in different soil layers, and SOC content and components are decreased with the increase of soil depth. SOC contents and components in 0-20 cm treated with organic fertilizer (M and MNP) are significantly higher than those treated with chemical fertilizer (NP and NPK) and CK. Compared with CK, M and MNP increase SOC content by 133.59% and 118.52% (P<0.05), easily oxidized organic carbon content by 51.73% and 48.20% (P<0.05), soluble organic carbon content by 61.54% and 53.21% (P<0.05), soil microbial carbon content by 68.34% and 113.04% (P<0.05), respectively. Except for soil microbial carbon, no significant difference is found in SOC contents and components in 20-40 cm under different fertilization treatments. Different fertilization methods significantly increase soil CPMI in 0-20 cm, and CPMI is the highest under M. In conclusion, applying organic fertilizer can improve soil quality and enhance soil carbon sink function.