Abstract: In order to study the stability difference of dump slope under different pore water pressure redistribution and evaluate the stability, according to the actual groundwater level distribution of a mine dump from August to September, the influence mechanism of water pressure redistribution on slope stability is analyzed. SLOPE/W module is used to simulate the slope stability difference and safety factor variation under different pore water pressure distribution. The results show that the redistribution of pore water pressure will change the pore space in the slope, accelerate the infiltration, and weaken the slope of waste dump in different degrees. With the decrease and expansion of the negative pore water pressure distribution range, the matrix suction of the slope changes and the safety factor first decreases and then increases. When the slope safety factor increases to 1.421, the groundwater level decreases by 30 m. It is close to the basement as a whole and will no longer affect the slope stability of waste dump.