In recent year, it is reported that roll and lateral vehicle motions are affected by the road input. However, there are few researches about a suspension control method which takes into consideration with the suspension characteristic that is change of tire side-force caused by suspension stroke and tire sideforce. In this paper, new semi-active suspension control method is proposed to reduce the vehicle vibration and vehicle lateral motion due to the road input. Firstly, a vehicle model including the suspension characteristic is constructed. Next, the time delay of the road input from the front wheel to the rear wheel is modeled with Pade approximation. The robust control system design which sets the lateral acceleration of the vehicle to one of controlled outputs is proposed. Finally, in order to verify the effectiveness of the proposed control method, the simulation is carried out by using the full vehicle model.