Abstract:The sloping farmland in the Loess Plateau accounts for 75% of the total cultivated land area in the region, resulting in serious soil erosion. It is of great significance for agricultural production and ecological environment construction to control the soil erosion of sloping farmland. Soybean is an important crop on sloping farmland in the Loess Plateau. However, at present,the ability of soybean to regulate runoff and sediment in this area needs further study. Taking the sloping farmland with soybean as the research object, and the ability of soybean to regulate runoff and sediment under different slopes and rainfall intensities were studied. The experimental design included five growth stages of soybean (seedling stage, initial flowering stage, full flowering stage, pod-forming stage and granulation stage), five slope gradients (3°, 5°, 10°, 15° and 20°), and two rainfall intensities(40 and 80 mm/h). The effect of soybean on regulating runoff and sediment was divided into two parts, which were reducing runoff and reducing sediment yield. Comprehensive comparative analysis was carried out using six indicators, which were runoff time, initial rainfall loss, runoff, sediment yield, reduced flow benefit (RRB) and sediment reduction benefit (SRB). The results showed that soybe an played an important role in regulating runoff and sediment. Compared with bare land, the runoff of the slope decreased by 10.75%~64.94% and the sediment yield decreased by 15.38%~84.24% from the seedling stage to the granulation stage. The RRB and SRB of soybean showed an overall increasing trend from the whole growth period, and they were inversely proportional to the slope. Similarly, with the increasing of rainfall intensity, the RRB and SRB of soybean decreased slightly and the difference was not significant, and the SRB value was always greater than RRB value, so it was found that soybean was more effective in reducing sediment than in reducing runoff. In summary, planting soybean on sloping farmland in the Loess Plateau had a positive effect on control soil erosion of sloping farmland, and the interception effect on sediment was stronger than the interception of runoff.