The effects of rainfall intensity and slope on erosion process for quaternary red soil was analyzed through indoor simulated rainfall test, and the test reveal the mechanism of slope erosion for quaternary red clay in hilly area of South China. According to the characteristics of topography and precipitation in the study area, we designed slopes of 10°, 15°, 20°, and rainfall intensity of 1.0, 1.5 and 2.0 mm/min to explore the influence of rainfall intensity and slope on the erosion process. The results showed that:(1) The initial slope runoff time decreased with the increase of slope and rainfall intensity; under the same rainfall intensity, the runoff coefficient was 20° > 15° > 10°; (2) While slope degree increased from 10° to 20°, the total amount of erosion and sediment yield increased by 0.46~1.98 times on the slope; when the rainfall intensity increased from 1.0 mm/min to 2.0 mm/min, the cumulative slope sediment yield increased by 1.37~3.85 times; (3) Under the condition of 1.0 and 1.5 mm/min rain intensity, the sediment yield on slope was dominated by <0.25 mm water-stable aggregates, and the water stability of > 0.25 mm was dominated by the slope erosion under the rainfall intensity of 2.0 mm/min; (4) The effects of slope and the rainfall intensity on runoff coefficient, erosion rate and cumulative sediment yield were significant (P<0.01),and the relationship between runoff and sediment yields could be described by power function. The results provide reference to reveal the mechanism of slope erosion in the quaternary red clay.