[Objective] To explore the effect of different rainfall intensity and slope gradient under the conditions of different cover on runoff and sediment reduction effect, and to quantitative determine the weight of erosion influence factors.[Methods] Use the methods of artificial rainfall and gray correlation analysis.[Results] (1) Compared with bare land, the slope with litter, gravel and ryegrass had a good effect on runoff and sediment reduction, reducing the flow of benefits to a maximum of 79.7%, the average current reducing benefits was 46.1%. Followed by ryegrass, with maximum flow reducing benefits of 68.9%. The third is gravel, with maximum flow reducing benefits of 68%. (2) Ryegrass flow reducing effect exists critical coverage, its value was in the 60% or so, when the coverage was more than 60% after the current reducing benefits, no longer increased. (3) Sediment reduction effect increased with the increase of coverage, the biggest sediment reduction effect of the litter, gravel and lawn were 98.8%, 64.6% and 88.1% respecitively. (4) Through gray correlation quantitative analysis on selected 8 influence factors and runoff had high correlation, correlation degree was more than 0.622 3.[Conclusion] The different test conditions and different cover on runoff and sediment yield had significant effect, the rainfall intensity and rainfall is larger on the factors affecting sediment yield, rainfall intensity, rainfall, cover and slope were 4 factors which had greater influence on runoff, the influence of correlation degree and correlation factors and runoff and sediment sequence for different types of soil.