Abstract: In order to solve the difficulty in using land for waste dump and reduce the production cost,the mining enterprise is going to dump a large number of waste soils outside the tailings dam.Therefore,in order to discuss the effect of dump slop on the safety of the tailings reservoir,the numerical method is adopted to study the change law of the seepage line,pore water pressure and anti-sliding stability before and after the dump slope.The results show that the key of the dump slope feasibility is the dump bottom layer's drainage performance and the dump soil's sliding resistance.The appropriate dump slop work can not only improves the tailings dam's stability,but also solves the waste dump problem in mining work,which can offer some references to the similar mining enterprise.