The car’s body was modeled by the EulerBernoulli beam model,and the car’s tires were modeled by the two springs with different spring index at both ends for the halfvehicle modal. The first two natural frequencies and model function of transverse vibration of moving vehicles over a smooth road were numerically solved. The transcendental equation and the eigenfunction were established by boundary condition based on the complex model function. The first two natural frequencies and the corresponding model function were obtained numerically, and the contributions of the speed of vehicle,the flexural stiffness of the car’s body and the stiffness of the tires were discussed via numerical examples.