As an important carbon reservoir in the Loess Plateau, the stability of soil organic carbon in the deep layer of silt dam greatly affects soil carbon storage capacity and carbon emission. In this study, the soil organic carbon content and its components of the silt dam profile in loess hilly-gully region were investigated to study the variation characteristics and influencing factors of soil organic carbon content and its stability under different utilization years and different deposition depths. Results demonstrated that:(1) Soil organic carbon (SOC) content in the deep layer of the dam was lower than that in the surface layer of the sloping farmland, and there was no obvious organic carbon enrichment phenomenon. The SOC content of dam land increased with the increasing of utilization years. (2) The contents of SOC, EOC, MBC and DOC in the dam land with different utilization years showed obvious surface aggregation phenomenon. The content of MBC, DOC and EOC was higher in 0-60 cm soil layer. (3) Compared with the shallow soil, the SOC in the deep layer of the dam had higher stability, long-term tillage in dam would reduce the stability of SOC in deep soil. (4) The dominant factors affected SOC stability in shallow and deep soils were different. The stability of shallow SOC was mainly affected by soil depth, organic carbon content and clay content, which could explain 50.4%, 19.6% and 11.8% of the variation, respectively. The stability of deep SOC was mainly affected by organic carbon content, soil water content and utilization years, which could explain 38.9%, 33.9% and 11.8% of the variation, respectively.