To gain a deeper understanding of the dynamic effects of concrete-faced rockfill dam (CFRD) on deep overburden in seismically active regions, seismic response analyses of CFRDs on deep overburden were conducted using a three-dimensional wave propagation analysis method that accounts for the dynamic interaction between the dam, overburden, and foundation, considering key factors such as valley width, overburden characteristics, and ground motion properties. The results show that edge effects near the abutments induce relatively large acceleration responses at dam crest regions in the vicinity of both abutments. The high-frequency filtering effect of the deep and soft overburden attenuates the acceleration at the dam crest in the valley section. Under strong seismic loading, the reduction in soil modulus and increase in damping further reduce the acceleration response at the dam crest in the valley dam segment. The local areas near the dam crest close to the abutments are identified as potential weak areas in terms of slope sliding stability, for which targeted reinforcement measures are recommended.