Abstract: A system and method of controlling a semiactive suspension is disclosed. The system and method effectively selects appropriate damping force curves for the dampers of the four wheels in accordance with both an output vertical acceleration signals from three vertical acceleration sensors installed on the dampers of three wheels and an output axle acceleration signal from an axle acceleration sensor installed on the axle. At the resonance frequency band of a car body, the system and method controls the suspension according to the vertical speeds and ride values, calculated from the vertical acceleration signals, thus reducing the uncomfortable riding effects of the vehicle. Meanwhile, at the resonance frequency band of the axle, the system and method controls the suspension with a higher damping force thus securing steering safety of the vehicle.