Abstract: While a vehicle running on the road, the vibration of vehicle and road are coupled and interacted. The vehicle is simplified into a two DOF vibration system and the road is dispersed as a multi-layer FEM system. Then considering the road and vehicle as a whole system, and each of them is a subsystem, a dynamic model of vertical vehicle-road vertical coupled system is established. Take this as the foundation, the dynamic equilibrium equation of vehicle-road system is deduced and the dynamic equilibrium equation is solved by regarding the pavement roughness as a stimulate function. By an example, the relation of vehicle speed, the wavelength and amplitude of road and vehicle dynamic load, vertical vehicle acceleration are analyzed numerically. It shows that road roughness and vehicle speed are the main factor which affect the dynamic property of the vehicle-road vertical coupled system. Therefore, it is important to control the road roughness. Results of this work agree well with some existing document results; thusly the reliability of the model is verified.