The dynamics of soil erosion play a critical role in shaping the spatial and temporal distribution of suspended sediment concentration (SSC) and particle size in rivers. However, the responses of SSC and particle size to soil erosion remain unknown under different seasons and terrains. This study examined soil erosion, SSC, and particle size in the Beiluo River Basin across various seasons and terrains. The results revealed the soil erosion was higher in summer (18.10 t & centerdot;ha(-1)) than in autumn (0.20 t & centerdot;ha(-1)), whereas the SSC exhibited the opposite trend, peaking (9158.0 mg & centerdot;L-1) in the hilly gully area during autumn. Suspended sediment particle sizes were predominantly concentrated in the <10 mu m and 10-50 mu m ranges. The relationship between SSC and soil erosion modulus was particularly strong in autumn (r = 0.929**) in the tableland gully area. Additionally, the response of SSC to soil erosion varied with particle size. Specifically, in summer, the strongest response was observed for coarser sediments (>100 mu m, r = 0.729**) in the tableland gully area, whereas in autumn, fine sediments (<10 mu m) exhibited a more pronounced response (r = 0.769**) in the tableland gully area. These findings enhance our understanding of the interactions among soil erosion, SSC, and particle size, offering valuable insights for the development and implementation of soil and water conservation measures.