In order to explore the effects of different nitrogen inputs on soil erosion and soil water-stable aggregates in red soil slope farmland, four nitrogen treatments including N1(300.00 kg/hm²), N2(225.00 kg/hm²), N3(150.00 kg/hm²) and N4(75.00 kg/hm²) were designed, and the runoff and sediment yield were measured during the whole growth period of silage maize. Meanwhile, the aggregate components with particle size >2,1~2,0.5~1,0.25~0.5 and <0.25 mm were obtained by wet screening method, and the content of water-stable aggregates (WSA_>0.25), mean weight diameter (MWD), geometric mean diameter (GMD) and parting dimension (PD) were calculated. The results showed that:(1) The characteristics of runoff and sediment yield of different nitrogen inputs were closely related to rainfall intensity. The runoff and sediment yields of N1 and N2 treatments were significantly lower than those of N3 and N4 treatments under the condition of low, medium and high intensity rainfall (P<0.01), and there was no significant difference in runoff and sediment yield between N1 and N2 treatment (P>0.05). Whereas, the differences in runoff and sediment yield were not significant among different treatments under extremely high intensity rainfall (P>0.05). (2) WSA_>0.25,GMD and MWD of N2 treatment were higher than those of the other three treatments, but the PD was relatively low. Additionally, there was a very significant positive correlation among WSA_>0.25, MWD and GMD, but an extremely significant negative correlation with PD, runoff and sediment yield. (3) The soil bulk densities of N1 and N2 treatments were significantly lower than those of N3 and N4 treatments (P<0.01), but the porosity and soil water holding capacity of N1 and N2 treatments were significantly higher than those of N3 and N4 treatments (P<0.05). Therefore, reducing 25% of nitrogen input at the local fertilization level will not aggravate soil erosion, and improve the soil physical properties to maintain the productivity of red soil sloping farmland.