Abstract: The aim of this study is to investigate the soil organic carbon (SOC) content and its influencing factors in citrus orchards in the Three Gorges Reservoir region, and to elucidate the mechanisms affecting SOC levels in the orchards. Leveraging actual measured data from 156 sample sites in the study area, this study considered potential variables affecting soil organic carbon content, such as topography, climate, and vegetation. The Random Forest (RF) model was employed to separately identify key factors that may influence the organic carbon content in three soil layers (0~10 cm, 10~20 cm, and 20~40 cm). Further, the Structural Equation Modeling (SEM) was utilized to explore the impact of key factors on soil organic carbon (SOC) content. The findings indicated: (1) Soil total nitrogen and annual average temperature were key factors affecting soil organic carbon, with their relative importance score gradually decreasing with an increase in soil layer depth. Specifically, the relative importance score of soil total nitrogen in the three soil layers were 35.96, 34.35, and 32.08, respectively, while those of annual average temperature were 7.68, 7.45, and 5.58, respectively.(2) A significant non-linear relationship existed between the key influencing factors and soil organic carbon, demonstrating a similar partial dependence pattern across all soil layers. (3) Soil total nitrogen had a significant positive effect on SOC across all observed soil layers (β=0.881 for 0~10 cm; β=0.829 for 10~20 cm; β=0.820 for 20~40 cm). The total effect of the annual average temperature on SOC was not significant, demonstrating a negative effect in shallower soil layers (β=-0.012 for 0~10 cm; β=-0.069 for 10~20 cm) and a positive effect in deeper layers (β=0.027 for 20~40 cm). Soil total nitrogen demonstrated the highest relative importance score and played a critical, and positive role in influencing soil organic carbon in citrus orchards, which highlighted the potential benefits of strategic nitrogen management to increase soil organic carbon storage.