Soil active organic carbon is the active part of soil organic carbon (SOC). Soil active organic carbon, which is an important index to measure soil quality and health status, can reflect the early changes of soil environment in the process of vegetation restoration and succession. However, in the barren sandy land of SOC, the influencing mechanism of long-term restoration succession affecting soil active organic carbon composition is still unknown. This study took Hedysarum mongolicum artificial shrub forest in Mu Us Sandy Land as the research object, selected Hedysarum mongolicum artificial shrub forest with no afforestation (CK) and afforestation life for 9 a, 18 a and 30 a, respectively. We explored the changes of soil dissolved organic carbon (DOC), microbial biomass carbon (MBC), readily oxidizable organic carbon (ROC) and SOC during the restoration and succession of Hedysarum mongolicum artificial shrub forest in Mu Us Sandy Land. The results showed that: (1) the soil carbon sequestration capacity of Hedysarum mongolicum shrub forest in Mu Us Sandy Land increased with the increase of restoration succession years. But there was a turning point in the restoration succession for 18 a, and the soil carbon sequestration rate slowed down in the restoration succession for 18-30 a; (2) DOC, MBC and ROC of topsoil 0-10 cm were sensitive to restoration succession, and the contents of active organic carbon in topsoil increased gradually during restoration succession; (3) The restoration succession years did not have a significant effect on the ratio of soil active organic carbon to SOC, nor did it significantly change the carbon pool activity. To sum up, the restoration succession of poplar wood shrub forest in Mu Us Sandy Land is conducive to the accumulation of soil active organic carbon and SOC. Whether the long-term restoration succession has a positive effect on soil active organic carbon sequestration need to study further.