Abstract: Pore water pressure is one of the important parameters to characterize the seepage and stability evolution of inner waste dump slope.In order to verify the rationality of the existing slope design parameters,taking the inner dump slope of Heshangqiao Iron Mine as the engineering background,based on the direct coupling method of Biot consolidation theory,numerical simulation analysis is carried out by using GeoStudio software to study the seepage law and stability of the inner dump slope under rainfall conditions,and explore the influence of rainfall intensity and duration on the pore water pressure of the slope.The distribution law and safety coefficience of pore water pressure in slope under different rainfall intensity are obtained.The results show that the rainfall infiltration range is mainly within 3~5 m below the surface of the slope of the waste dump.Rainfall infiltration rate is mainly affected by the relative size of soil permeability coefficient and rainfall intensity.The design parameters of the waste dump slope in Heshangqiao can remain safe and stable during continuous heavy rainfall,but the non infiltrated rainfall on the slope surface needs to be discharged in time through the drainage ditch.