Abstract: The dynamic response history of a 420 meters long span bridge under the excitation of seismic wave was analyzed. The computation results using Rayleigh and Caughey damping models were compared with the exact solution, and the differences between the effects of the two damping models were pointed out. Further discussions were made about the applicability and validity of different damping models. Finally, some caveats about the application of Caughey damping model were proposed at the end of the paper.