Abstract:In order to determine the change characteristics and influencing factors of soil organic carbon (SOC) and easily oxidized organic carbon (EOC) under different vegetation types of engineering deposits, four types of sample plot of tree, shrub, grassland and bare land were set up in this study, and the soil samples were collected at the depth of 0—10, 10—20, 20—40, 40—60 and 60—80 cm. The organic carbon components and physical and chemical properties of the soil were determined by principal component analysis and correlation analysis. The results showed that: (1) There were significant differences in SOC content among different vegetation types. The mean values of SOC in tree plot, shrub plot, grassland plot and bare soil were 45.73, 41.81, 34.75 and 21.11 g/kg, respectively. Vegetation restoration significantly increased SOC content, especially in surface soil. (2) Soil carbon pool activity (ratio of active organic carbon to inactive organic carbon) of tree plot and shrub plot was significantly higher than that if grassland plot, and SOC of tree plot and shrub plot was easier to be absorbed and utilized by plants. (3) Total nitrogen (TN), total phosphorus (TP) and hydrolysis nitrogen (HN) were significantly positively correlated with SOC and EOC (p<0.05), and played a major role in the improvement of SOC. Therefore, mixing legumes with nitrogen fixation effect was beneficial to the improvement and accumulation of SOC.