Abstract: Background A systematic understanding of the distribution characteristics and driving mechanisms of soil C, N and P under different vegetation types is of great significance for scientifically evaluating the soil and water conservation effects of vegetation restoration measures and optimizing vegetation configuration on the Loess Plateau. Methods This study selected typical forestland, shrubland and grassland in Wuqi County, Shaanxi Province, as the research objects. The vertical distributions of soil C, N and P contents and their ecological stoichiometry across the 0-200 cm soil profile were systematically analyzed, and Pearson correlation analysis, redundancy analysis (RDA) and random forest models were applied to identify the relative contributions of different environmental factors to variations in soil C, N and P. Results 1) Within the 0-200 cm soil profile, soil organic carbon (SOC), total nitrogen (TN) and total phosphorus (TP) exhibited clear vertical differentiation under different vegetation types. SOC and TN contents generally decreased with increasing soil depth, whereas TP showed relatively weak vertical variation. Considerable amounts of nutrients were retained in deep soil layers. 2) Significant differences in soil C, N and P contents and their stoichiometric characteristics were observed among vegetation types. Compared with forestland, shrubland and grassland exhibited higher soil nutrient and water contents across multiple soil layers, indicating a strong influence of vegetation type on soil nutrient distribution. 3) Soil stoichiometric characteristics varied markedly with soil depth, with soil C:P and N:P ratios decreasing significantly, indicating an increased relative importance of P in deep soil layers and a weakened coupling between soil C, N and P. 4) Driving factor analysis revealed distinct dominant controls for different nutrient elements. Variations in SOC and TN were mainly associated with soil chemical properties, whereas variations in TP were more strongly influenced by soil physical properties and topographic factors, indicating that the formation and migration of SOC and TN are mainly regulated by biogeochemical processes, whereas the distribution of TP is more constrained by physical processes and parent material. Conclusion These results highlight the necessity of considering deep soil nutrient processes in vegetation restoration and soil and water conservation practices on the Loess Plateau. Optimizing the configuration of forest, shrub and grass vegetation according to local topographic conditions is essential for enhancing long-term soil and water conservation benefits and maintaining ecosystem stability.