We study the characteristics of runoff and erosional sediment yield on purple soil slopes by artificial rainfall simulation experiments. The result reveals that the initial runoff yield duration of purple soil slope decreases as rainfall intensifies, and the initial runoff yield is remarkably affected by the slope gradient under small rainfall intensity. The total volume of runoff on purple soil slope tends to rise with the increase of slope gradient and rainfall intensity; whereas rainfall intensity has no obvious influence on the total runoff on a steep slope. The sediment yield on purple soil slope goes up as the slope gradient and rainfall increases, for instance, when the slope gradient is 10°, 15°, and 20°, the sediment yield is relatively large, ranging from 3 106.03 g to 8 117.09 g . In view of this, effective water and soil conservation measures should be implemented on soil slopes larger than or equal to 10 degrees.