An equivalent static method is employed in most codes and specifications for vessel collision design of bridges,in which the dynamic nature of vessel-bridge collision is ignored.Higher requirements to the researchers and heavy calculation are required for the finite element numerical simulation method.Compared to the shortcomings of the above methods,with reference to the concept of the earthquake response spectrum,the design impact spectrum method was proposed.Through numerical simulations of the ship-rigid wall collision,81 impact force time histories associated with different cases were obtained.The displacement amplification factor of single-degree-of-freedom(SDF)system with different periods and damping ratios were calculated under the impact force time histories.Then a design impact spectrum of vessel-bridge collision was obtained by finding statistical regularity of the displacement amplification factor.Finally the application steps of the design impact spectrum were provided.