[Objective] The relationship between biological measures and their influence factors on soil erosion on steep slopes were studied, in order to provide theoretical basis for gully control and vegetation measure allocation of soil and water conservation.[Methods] Two slope gradients and seven herb vegetation models were set up by small plots, and runoffs and soil losses of the plots were monitored from June to September in 2018.[Results] Compared to bare plot, the average runoff at 1:1.5 and 1:1.2 ratio slope with herb vegetation was declined by 27% and 26%, and the average soil loss reduced by 52% and 21%, respectively. As the slope steepness increased from 34° to 40°, runoff didn't show significant increase, but the amount of soil loss increased markedly. The dominant rainfall factors influencing runoff and sediment were precipitation, I₃₀, E and EI₃₀. The correlations among runoff, sediment and rainfall increased with the increase of slope steepness. The mixture of Bromus inermis and Medicago sativa L had the best effect on reducing runoff and sediment. The soil erosion control effect of mixed sowing of Bromus inermis, Medicago sativa L and Poa annua L was better than that of single sowing. With the increase of vegetation coverage, the sediment reduction effect of 1:1.2 slope was gradually enhanced, and when the vegetation coverage was more than 50%, the effect of sediment reduction was close to 1:1.5 slope.[Conclusion] Under the mixed herb configuration of Bromus inermis and Medicago sativa L. the 1:1.2 ratio slope could be used for gully erosion control, which could save 20% of the gully slope cutting area.