Researches on saturated-unsaturated soils became a hot issue in resent years. In fact

it is very difficult to analyze the mechanical behaviors of soil because of the pore water pressure’s existence. Based on the relationship between permeability and matric suction

numerical simulation of unsteady seepage analysis of an ideal isotropic embankment is presented. And the dynamic change of the seepage field is temporally and spatially discretized and inducted into the stability analysis of the embankment slope. Regularity of the minimum safety factor of the slope is discussed by applying the limit equilibrium theory and Morgenstern-Price slice method to show the inherent relation between seepage and landslide.