The Grain for Green Programme (GGP) was launched in Loess Plateau, China in 1999. The implementation of a large number of ecological restoration projects may inevitably affect the soil carbon pool, creating a need to evaluate the soil carbon sink benefits of ecological restoration. This study determined the effects of three ecological restoration patterns (natural secondary forest, artificial ecological forest, and artificial economic forest) on the soil organic carbon (SOC) content of a cropland site in the gullies of Loess Plateau. The SOC and particle size were measured across 12 types of land use/cover at 20 depths representing 0-400 cm. The results revealed that (a) the SOC storage of natural secondary forests was (166.40±42.90) t/hm², which was significantly higher in the natural secondary forest than that in cropland in the slope ((58.73±4.73) t/hm²) by 107.67 t/hm². An increase in SOC storage of 89.54% and 78.11% in the artificial ecological forest ((111.32±13.30) t/hm²) and the artificial economic forest ((104.60±7.10) t/hm²), respectively. (b) We found increases in the 0-60 cm SOC content from (11.03±7.51 to (2.40±0.93) g/kg (P<0.05), which showed a certain degree of surface aggregation. There were small vertical changes in mean SOC content of (1.81±0.88) g/kg below 60 cm. (c) The higher SOC storages in the three restoration patterns than that in cropland by 109.43%, 76.43%, and 65.06% in 1-4 m layers, respectively. Additionally, the deep SOC storage of natural secondary forest ((77.81±8.40) t/hm²), artificial ecology forest ((65.55±7.71) t/hm²), and artificial economic forest ((61.32±3.16) t/hm²) accounted for 46.76%, 58.89%, and 58.62% of the 4 m organic carbon storage, respectively. These results suggest the importance of deep SOC content in the soil carbon pool, and highlight that ecological restoration affect the carbon sink capacity. The natural secondary forest and artificial mixed forest may help to mitigate C emissions in the gullies of the Loess Plateau.