To understand the impact of vegetation restoration on soil carbon in the Loess Plateau in China, soil samples (0-100 cm) were collected from grass land, Pinus tabuliformis, Armeniaca sibirica, A.sibirica and P.tabuliformis mixed plantations and Hippophae rhamnoides in Wuqi County, and then the distribution characteristics of soil carbon (SOC, SIC and TC) contents and their influencing factors were analyzed through random forest model and other methods. The results show that the average TC is ranged from 1.685 to 1.898 g/kg, average SOC content is in the order of A.sibirica (0.368 g/kg)> grass land (0.299 g/kg)> H.rhamnoides (0.250 g/kg)> P.tabuliformi (0.233 g/kg)> A.sibirica and P. tabuliformis mixed plantations (0.209 g/kg), and average SIC content is 5.6 times higher than that of SOC. SIC is not significantly different in all restored vegetation in 60-100 cm soil layer, SOC in 0-20 cm soil layer is significantly higher (P<0.05) than that in 20-100 cm soil layer in all plant communities except for P.tabuliformis. Slope aspect and gradient, elevation, land use type, soil moisture and the contents of soil clays, available phosphorus and nitrogen can explain a total of 78%, 24% and 77% of the variation in SOC, SIC and TC respectively. The elevation, slope aspect and soil moisture are the main factors influencing soil carbon content in the study area (P<0.05). In general, the influence of topographic factors and soil physiochemical properties should be fully considered in the process of vegetation restoration on the Loess Plateau. This study can provide basic data and scientific references for the accurate assessment of soil carbon stocks in plantation forests and their ecological benefits.