To reveal the effects of crushed corn straw returning on soil erosion characteristics at the black soil hillslopes, the simulated rainfall experiments were carried out based on different amounts of crushed corn straw returning (0, 25%, 50%, 75% and 100%) under different slope gradients (3°, 5° and 7°). The results showed that the crushed corn straw returning could regulate runoff, and delay the runoff-yield time; and thus, the runoff rates and runoff values decreased. Moreover, with the increasing amounts of the crushed corn straw returning, the runoff-yield time delayed more and the mean runoff velocity obviously decreased. For the 3° hillslope, the 25% and 100% of crushed corn straw returning treatments showed better runoff regulation effects; while for the 5° and 7° hillslopes, the 50% and 75% treatments showed the better. Furthermore, the crushed corn straw returning could decrease the sediment rates and soil erosion to a certain extent. When the amount of the crushed corn straw returning was lower (<50%), the sediment rates and soil erosion were also lower under gentle slope gradients (3° and 5°), which illustrated that the treatments showed relatively better soil erosion regulation effects. Among them, the soil erosion regulation effect for the 25% of crushed corn straw returning treatment could reach 74.1% under the 3° slope gradient. When the amount of the crushed corn straw returning was greater (>50%), the soil erosion regulation effects increased with the increases in the slope gradients. Among them, the soil erosion regulation effect for the 100% of crushed corn straw returning treatment could reach 72.1% under the 7° slope gradient. Therefore, it is necessary to select appropriate corn straw returning patterns and amounts based on concrete slope gradients and other topographic characteristics in the practice of agricultural production.