This study examined sediment particle sorting dynamics across rainfall intensities and slope angles on Loess Plateau soils., and to better understand the processes of sediment detachment, transport, and deposition, this study focused on two pedological types: primary loess (PL) and sandy remolded loess (SRL).. Simulated rainfall experiments were conducted on 10 m slope lengths under different slope gradients (5°, 7.5°, 10°, and 15°) and rainfall intensities (60 mm/h and 90 mm/h) to analyze slope erosion processes and sediment particle size variations. The results showed that: (1) Under 60 mm·h?1 rainfall, silt-fine sand fractions dominated both soils (PL:82-95%; SRL:65-88%), constituting the primary erosion components.mm/h Threshold slopes emerged at 5°-7.5°(PL) and 7.5°-10°(SRL), inducing divergent silt-fine sand transport regimes. At a rainfall intensity of 90 mm/h, the sediment particle size distribution of both soils became more similar to that of the undisturbed soils, and with rill formation leading to elevated clay fractions in transported sediments. (2) At a rainfall intensity of 60 mm/h, the enrichment ratio (ER) of clay particles in both primary loess and sandy remolded loess was less than 1, the ER of silt particles was close to 1, and the ER of fine sand particles was greater than 1, indicating that sediment erosion was primarily dominated by fine sand enrichment. At 90 mm/h, the enrichment patterns of the two soils reversed, with fine sand enrichment remaining dominant for loess, while clay enrichment became dominant for sandy loess. (3) Under 60 mm/h, rainfall, the median particle size (d50) of both loess types was generally higher than that of undisturbed parent materials, and the d50 values decreased over time as rainfall continued, and also decreased with increasing slope gradients, indicating surface soil fines enrichment processes on both loess and sandy loess slopes. Threshold slopes existed for primary loess (5°-7.5°) and sandy remolded loess (7.5°-10°) respectively, beyond which surface fines enrichment stabilized over time. At 90 mm/h rainfall intensity, the sediment particle size distribution of both soils stabilized more rapidly. The d50 values of loess remained higher than parent materials, whereas those of sandy loess became lower than parent materials. Rainfall induced surface fines enrichment on loess slopes, but promoted surface coarsening on sandy loess slopes through selective particle sorting. This research elucidates particle sorting mechanisms governing loess slope erosion, advancing predictive models for sediment transport dynamics. of the two soil types, providing data support and theoretical insights for a deeper understanding of the mechanisms of loess slope erosion.