Taking the deep foundation pit slope of second-line ship lock for Dayuandu navigation-power junction as an example,combined with the saturated-unsaturated theory, this paper establishes a two-dimensional numerical model by seepw module and slopew module in the finite element software Geo-Studio to analyze the seepage state of the slope under heavy rainfall,through which the change of variation of water content and pore water pressure inside the slop,the safety factor and the variation of the slip surface are obtained.The results show that with the increase of rainfall duration,the slope moisture content increase gradually,the rainwater continues to infiltrate into the deeper soil,the groundwater level rises continuously,the matrix suction gradually dissipates,the surface of the slop forms a transient saturation zone,and the safety factor decreases.After the rainfall stopped,the water gradually flowed out of the slop,the water content gradually decreased,the underground water level decreased gradually,and the positive hole pressure decreased,the matrix suction gradually recovered,and the safety factor increased gradually.Rainfall infiltration has a great influence on the shallow soil of the slope,has little effect on the deep soil,and forms shallow damage generally.