The municipal solid waste landfill is the main place to hold the waste soil and slag.Due to the difference in the filling material and the compaction method, it is of practical significance to study the influence of initial seepage field on the calculation of rainfall infiltration characteristics and stability of the municipal solid waste landfill.Therefore, taking the municipal solid waste landfill in Bujiuwo, Shenzhen as the research object, a numerical calculation model was established based on the unsaturated seepage principle and unsaturated soil strength theory.The calculation schemes of different initial seepage conditions and rainfall intensities are designed. Then the seepage characteristics and the variation law of safety factor of the slope under rainfall are revealed. The results show that the initial seepage field and rainfall intensity have significant influence on the rainfall infiltration characteristics and therefore stability of the municipal solid waste landfill. The peak value of vertical velocity and the increase rate of pore water pressure are positively correlated with the initial matrix suction. When the rainfall intensity is 3.5 mm/h, the saturation time of monitoring point 1 is 10.9, 20.2, 25.5 h and the corresponding initial matrix suction equals to -25, -50, -75 kPa, respectively.Rainfall intensity,velocity of flow and volume water content are positively correlated with pore water pressure in vertical direction.When the initial matrix suction is -25 kPa and the rainfall intensity is 3.5 mm/h, the safety factor of the waste dump slope decreases obviously, and necessary engineering measures should be taken.