The dominant seepage layer usually has strong permeability, which has a great influence on the Infiltration process and stability of the whole slope. Insufficient research on the influence of dominant seepage layer interlayers on the seepage characteristics and stability of slopes under intermittent rainfall conditions, a rainfall infiltration model of silt soil slopes with dominant seepage layer was established by using finite element software Geostudio. Based on the saturated-unsaturated seepage theory, changing the anisotropy ratio of the dominant seepage layer, the location of the dominant seepage layer, and the thickness of the dominant seepage layer in the slope, the infiltration process at the moment of rainfall was simulated, between stopping rain, and after rainfall under the condition of intermittent rainfall, and the change rules of seepage rate, volumetric water content, and safety coefficient in the slope was revealed. The results show that the seepage velocity at the slope shoulder increases with the increase of the anisotropy ratio of the dominant seepage layer. In the spatial position, the volume water content of the dominant percolation layer shows an N-shaped trend with the elevation, and if the position of the dominant layer is changed by 1 m, the n-shape will be shifted along the x-axis in the graph of the change of volumetric water content with the elevation by 1.5 m. The lower the position of the dominant seepage layer in the slope, the more unstable the slope is.