Under the action of reservoir water seepage，the change of water level will produce unsteady seepage，and the seepage property of soil will influence the distribution of water pressure.Seepage analysis is carried out on anti-dip rock bank slope under different water level by using the finite element Phase2 software.The influence of slope stability is studied under different water level variation rate and slip permeability coefficient.When the permeability coefficient of landslide is certain，the greater variation rate of reservoir water level，the more obvious variation of safety factor.When the variation rate of reservoir water level is certain，the smaller permeability coefficient of landslide，the more obvious variation of safety factor.When the falling rate of reservoir water level and the permeability coefficient of landslide is larger，the bank slope is more likely to be damaged.