Abstract: Clarifying the particle size characteristics of eroded sediment from typical aeolian sandy soil is key to studying soil erosion issues in the coarse sandy hilly region. Methods Using wind tunnel experiments and rainfall simulation experiments, this study investigated the variations in particle size characteristics of eroded sediment from typical aeolian sandy soil under four different erosion dynamic actions (single water erosion, single wind erosion, wind erosion followed by water erosion, and wind-water-wind compound erosion), with two slope gradients (10°, 15°), three rainfall intensities (60 mm/h, 90 mm/h, 120 mm/h), and three wind speeds (7 m/s, 9 m/s, 11 m/s). Results 1) Compared to single erosion, wind erosion followed by water erosion enhances the enrichment of both silt and very coarse sand particles. In contrast, the wind-water-wind sequential erosion process results in the highest enrichment rate of fine sand among the four erosion scenarios. 2）Under all four erosion conditions, fine particles (Silt、Very fine sand and Fine sand) exhibit preferential enrichment. The enrichment capacity of different erosion types for fine particles follows the order: wind erosion followed by water erosion > single wind erosion > wind-water-wind sequential erosion > single water erosion. The enrichment rate of fine particles increases significantly with slope gradient, and this effect is more pronounced under heavy rainfall conditions. Regarding the enrichment capacity for coarse particles(Medium sand、Coarse sand and Very coarse sand), except for the case of wind erosion followed by water erosion—which shows the strongest enrichment for both coarse and fine particles—the overall trend is opposite to that observed for fine particles. 3) The mean weight diameter of eroded sediment was significantly affected by erosion type, showing the following order: single water erosion > wind erosion followed by water erosion > wind-water-wind compound erosion. Conclusion These results reveal the hierarchical controls of combined erosion dynamics and the slope gradient-rainfall intensity interaction on particle size sorting, providing a theoretical basis for differentiated management in regions affected by coupled aeolian-fluvial erosion.