In view of the fact that drawdown will change the hydraulic gradient in a slope, which will lead to the instability of the slope, the limit analysis method and strength reduction method were used to establish a two-dimensional water-bearing slope model, the safety factor F_s of the slope was determined by optimization iteration, and compared with the safety factors obtained by the stability chart and the finite element method. The influences of drawdown, nonhomogeneity, anisotropy and slope angle on the slope stability were explored. The results show that when the water level keeps constant, the safety factor of the slope increases with the increase of the heterogeneity coefficient; the increase of the anisotropy coefficient will reduce the safety factor and increase the possibility of slope instability; the slower the slope, the more significant the influence of water level height on the safety factor of the slope; under the same conditions, the stability of the slope is more affected by the anisotropy. The analysis results can provide a reference to the stability assessment of slopes during the drawdown process of the water level in practical engineering.