A general and efficient method is proposed for the resolution of the dynamic interaction problem between a bridge,discretized by a two-dimensional finite element model,and a dynamic system of vehicles with five degree of freedom running at a prescribed speed.Establishing the equations of motion for the bridge and the vehicles respectively,an iteration solution method is presented to analyse the coupling vibration reponse of vehicle-bridge system based on the same displacement and coupling force at the interface.The Newmark method is used for solving the motion equations.The numerical method is validated availability and feasibility through comparing the result of the text with the analysis of Runge-kutta method.Because of the response of bridge resting with some low mode,the dimension of matrix are reduced furthest,at the same time,the velocity of computing are improved.This method could be used for any intricate bridge.