Abstract: To investigate the influence of the traveling-wave effect on the longitudinal seismic response of road underpass tunnels in soft soil sites, a three-dimensional integrated finite element model of soft soil - underpass tunnel was established using ABAQUS. The traveling-wave effects were simulated by inputting seismic waves with fixed time delays at different sub-surfaces of the model base. Seismic response analysis was performed using the implicit dynamic time-history analysis method. The internal forces, tensile damage characteristics, and joint deformations under longitudinal uniform and non-uniform seismic excitations were comparatively analysedwithin the tunnel were compared between uniform and non-uniform excitation conditions. The results indicate that as the seismic wave delay decreases, the peak shear forces at the column bases and sidewall bases of the buried section frame increase; regardless of whether the excitation is uniform or non-uniform, tensile damage in the underpass tunnel mainly occurs at the interface between the ceiling slab and longitudinal beam of the buried section frame; compared to uniform excitation, non-uniform excitation significantly amplifies the tensile damage in the buried section frame and the joint deformation of the entire tunnel; for long, segmental tunnels with open-section–buried-section connections, it is recommended to account for the adverse effects of traveling wave phenomena to enhance the seismic safety and resilience of the tunnel.