Abstract: Rainfall is one of the major causes for instability and failure of slopes,as a result,slope sliding and destruction are closely related to rainfall infiltration.This paper selected the eastern slope of the open pit on the west side of the Ⅶ orebody of the Tonglüshan Ancient Copper Mine site as the analysis object.Firstly,numerical calculation models were set up according to the engineering hydrogeological conditions and the occurrence of the investigated slope.Then,by using the SEEP/W module of the GEO-STUDIO software,the internal seepage characteristics of the slope under different rainfall intensities were simulated.Finally,combining with the SLOPE/W module,the coefficients of slope stability under various rainfall conditions were calculated.The results have shown that with the increase of rainfall intensity,the internal seepage field of the eastern slope of the open pit mine changed significantly,and the coefficient of slope stability was negatively correlated with the rainfall intensity.