Since vehicle tires undergo excitation from the road, the sprung mass vibration couples that of the tires. In order to effectively attenuate the vibration of the vehicle, a full vehicle model with active suspension is established and decoupled using a differential geometry method. In the decoupled suspension system, the heaving, pitching, and rolling motion of the sprung mass are independent of each other and become separate linear subsystems, that can be controlled separately. An attenuation control rule is designed to attenuate the vibration of the decoupled suspension system. The simulations show that the vibration is greatly attenuated, which indicates that the control algorithm is effective.