Abstract: As a common composite site, the effect of the hill-water filled valley composite topography on the ground motion is currently unclear. Therefore, the coupling of soil and liquid in finite domain was realized by theoretical analysis, the seismic analysis of hill-water filled valley composite topography under arbitrary oblique incident P- and SV-waves by finite-infinite element method was studied, and the effect of the relative position between hill and water filled valley on the ground motion was discussed. New findings of this paper include: (1) The hill existing in the incident side of seismic waves of the water filled valley, can restrain the amplification of the ground maximum horizontal acceleration on the “near” edge of the valley of incidence of seismic waves for P and SV waves; (2) For SV-waves with overly critical angles and the hill existing in the incident side of seismic waves of the water filled valley, the ground maximum horizontal acceleration on the “far” edge of the valley of incidence of seismic waves is amplified instead; (3) The relative position between hill and water filled valley, incident wave type and the critical angle have significant influence on the displacement spectrum at both ends of the composite topography.