In the existing studies of coupled vibration on vehicle-bridge system, when establishing vehicle dynamics model, vehicles differential motion equations of position and attitude coordinates are derived by traditional kinetics analysis method the second kind Lagrange equation and Newton-Euler equation [1~5].This traditional kinetics analysis method results in that the vehicle models kinetic equations are needed to be deduced manually and the vehicle models are not detailed.With the requirement of detailed vehicle models, the nonlinear property of the vehicles makes it very difficult to establish the vehicle dynamics model manually.