Abstract: As a common composite terrain, the effects of the irregular topography of hill and water-filled valley on the ground motion are currently unclear. Therefore, the coupling of soil and liquid in finite domain is realized through the theoretical analysis, the seismic analysis of irregular topography of hill-water-filled valley under oblique incident P- and SV-waves by the finite-infinite element method is conducted, and the effects of the relative position between the hill and the water-filled valley on the ground motion are discussed. The new findings of this study include: (1) The hill located at the incident side of the seismic waves of the water-filled valley can restrain the amplification effects of the maximum horizontal acceleration of ground on the "near" edge of the water-filled valley under P- and SV-waves. (2) For the SV-waves with overly critical angles and the hill located at the incident side of the seismic waves of the water-filled valley, the maximum horizontal acceleration of ground on the "far" edge of the water-filled valley is amplified instead. (3) The relative position between the hill and the water-filled valley, the seismic wave types and the critical angles have significant influences on the displacement spectra at both sides of the irregular topography.