Combined with the typical prestressed concrete continuous-beam bridge with 17m+28m+17m span over the main channel of the Central Line of South-to-north Water Transfer Project, two finite element models of this bridge, one considering and another without considering the pile-soil action, were built by the specialist bridge analysis software MIDAS/Civil 2011. The main vibration mode and its frequency were calculated by the self-vibration analysis, and the seismic response of the bridge was given out by the SRSS method of response spectrum method. Based on the calculations, the effect of pile-soil action on the dynamic characteristics and seismic behaviors of the bridge was studied. The results show that the pile-soil action brought the bridge structure into flexible, which led to the smaller vibration frequency but had no influence on the top two vibration modes. It also led to the larger displacement at top of piers and midspan of continuous-beam and the smaller internal forces of brake pear under the seismic action.