The purpose of this study was to evaluate the soil carbon sink effects of long-term vegetation restoration on the Loess Plateau. A commonly method of spatial and temporal substitution was applied to study the change characteristics of soil organic carbon content and corresponding reserves of eight vegetation succession sequences in the Ziwuling area among nearly 150 years, also analyzed vegetation factors affecting the soil organic carbon reserves changes. The results showed that from slope farmland to Quercus wutaishanica Mary. communities, which was in its highest climatic stage, soil organic carbon contents and corresponding reserves increased significantly, showing a rapid increase in the early stage of succession (grassland communities) and a stable change in the later stage (arbor communities). Soil organic carbon content decreased rapidly as the soil layers deepened in profile. The soil organic carbon content in 0-5 cm soil layer differed significantly from those in 5-20 and 20-40 cm soil layers (P < 0.05), indicating a significant surface aggregation effect of soil organic carbon accumulation. Both litter biomass and fine root biomass were increased with succession time, while litter biomass was more conducive to increasing soil organic carbon reserves. A highly significant power function relationship was found between soil organic carbon reserves and vegetation restoration time for 0-5 and 0-20 cm soil layers, also soil organic carbon storage in different soil layers showed a significant linear correlation (P < 0.001). Long-term vegetation succession had a significant soil carbon sink function. The forests and grasslands restoration in the Loess Plateau should be premised on the distribution patterns of natural vegetation zones and promote its natural succession in the future, thus could further enhance the potential of soil carbon sinks capacity in the region.