Abstract: Coupled basin-mountain terrain is a common complex site, but the combined effect of such sites on ground motion is currently not clear. Therefore, the scattering of seismic waves (plane P, SV and Rayleigh waves) by coupled basin-mountain terrain is investigated by an accurate finite element-indirect boundary integral equation method (FEM-IBIEM) coupled method. Through detailed numerical analysis, it is shown that there exists significant dynamic interaction between the basin and its neighboring mountain, and the total response characteristics mainly depend on the effects of spatial location and geometric characteristics of the mountain, the frequency and angle of the incident waves, etc. Overall, for the vertical incidence of P waves, the mountain has significant amplification effects on the displacement amplitude in the basin. For the incidence of SV waves, the effects of the mountain on the nearby basin are smaller and different locations within the basin may exhibit completely different amplification or de-amplification features. For the incidence of Rayleigh waves coming from the mountain's side, the mountain mainly has a shielding effect on the basin. Meanwhile, for the incidence of waves coming from the basin's side, the mountain may have a notable amplification effect on the basin for low frequency waves. In general, the influence of nearby high mountains on the alluvial basin seems greater. In consideration of the significant effect of the mountain on the amplitude and frequency characteristics of the dynamic response in the basin, the actual simulation of ground motion in basin needs to consider the impacts of the adjacent mountain.