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Studying hillslope soil erosion processes in the black soil region is of great importance to black soil conservation and national grain production security. A rainfall simulation study was conducted to examine the effects of rainfall intensity and topography (slope gradient and slope length) on hillslope soil erosion processes. The experimental treatments included two rainfall intensities (50 and 100 mm/h) of representative erosive rainfalls in the black soil region, two common slope gradients (5°and 10°) and two slope lengths (5 and 10m). Each treatment had two replications. The results showed that runoff was increased by 1.4~12.4 times and 0.1~3.1 times, respectively, when rainfall intensity or slope length was increased under different treatments. Effects of slope gradient on runoff were complex, which were affected by both rainfall intensity and slope length. Rainfall intensity, slope gradient and slope length had important effects on hillslope soil loss. Soil loss was increased by 4.2 times when rainfall intensity was increased from 50mm/h to 100mm/h, and it was increased by 04 times for increasing slope gradient from 5° to 10° and 0.5 times for increasing slope length from 5m to 10m, which indicated that rainfall intensity had the most significant effects on hillslope soil loss. When rainfall intensity, slope gradient and slope length were increased simultaneously, soil loss was increased by 18.0 times, which suggested that the comprehensive effects of three factors were much greater than those of each single factor or the combination of two factors. Runoff had the strongest correlation with rainfall intensity, followed by coupling effects of rainfall intensity—slope length and coupling effects of rainfall intensity—slope gradient—slope length. Soil loss had the strongest correlation with coupling effects of rainfall intensity—slope gradient—slope length, followed by rainfall intensity and coupling effects of rainfall intensity—slope length. According to these observed data, the empirical equations for predicting runoff and soil loss were also established.