Abstract: The vehicle, pavement and bridge are considered as an entire system. The vehicle is modeled as a multi-rigid body connected by springs and dampers, the asphalt pavement as Kelvin model and boundless beam, the concrete pavement and bridge as a Euler-Bernoulli beam. Vertical vibration equations of the system are formulated by means of the principle of total potential energy with a stationary value in elastic-system dynamics and the ‘set-in-right-position’ rule for formulating matrices. The covariance equivalence method is used to establish the unsteady model of wheel random inputs. The dynamic responses for the coupling vehicle-pavement- bridge system with elastic supports are researched. The results show that when other parameters are idential, the impact factor to the concrete pavement is about1.35 times of that to the asphalt pavement; the impact factor to the rigid bearing is about 1.60 times of that to the rubber bearing, and when the velocity increase to more than 33.4m/s, effect of the rubber bearing to the impact factor is small.