[Objective] The patterns of soil erosion on slopes in the Xin’an River basin were evaluated in order to provide scientific support for regional soil erosion control and sustainable ecological development. [Methods] Through artificial rainfall simulation experiments,the runoff and sediment yield processes,and their differential erosion characteristics were systematically analyzed under different combinations of rainfall intensity and slope gradient for yellow soil and red soil in the river basin,and a quantitative relationship model between hydrodynamic parameters and sediment yield intensity was established. [Results] ① The runoff rate and sediment yield rate on the slopes of both yellow soil and red soil exhibited a steep initial increase during rainfall onset,followed by gradual stabilization,with both increasing with higher rainfall intensity and slope gradient.Red soil slopes demonstrated higher runoff and sediment yield capacity than yellow soil slopes,particularly under a rainfall intensity of 60 mm/h.② Rainfall intensity and slope gradient synergistically exacerbated runoff and sediment erosion,with rainfall intensity dominating the runoff and sediment transport processes on red soil slopes.When the slope gradient reached 15°and rainfall intensity increased to 60 mm/h,the contribution of slope to sediment loss on yellow soil slopes increased to 59.06%.③ A high correlation was observed between runoff and sediment yield on both soil types.Yellow soil slopes generally exhibited a nonlinear relationship characterized by Y=a/[1+exp^-b（X-c）].In contrast,due to rapid saturation caused by poor structure,red soil slopes showed synchronous linear growth between sediment yield and runoff yield under a rainfall intensity of 60 mm/h,described by the function Y=a+bX.④ Among the slope hydraulic parameters,average velocity （V） could effectively predict the sediment yield trend of yellow soil （R²=0.52）,while the Froude number （F_r） was more suitable for predicting the sediment yield dynamics of red soil （R²=0.44）. [Conclusion] This study clarifies the coupling mechanisms of rainfall intensity and slope gradient in soil slope erosion within the Xin’an River basin.It is recommended that rainfall intensity regulation should be strengthened in red soil areas,while slope management should be emphasized in yellow soil areas to curb the exacerbation of soil erosion.