The purpose is to present a new robust strategy in controlling the semi-active suspension system. The strategy utilized the sliding mode model-following control scheme. A quarter-car model was used in the project, and the proposed controller was easy to be implemented, and it was not necessary to measure the road signal and damper force. An approximate ideal skyhook system was used by the controller as a reference model, and the control law was determined so that an asymptotically stable sliding mode would occur in the error dynamics between the plant and the reference model states. A uniform reaching law was adopted to improve the dynamic quality of sliding mode motion. The performance of the controller has been compared with the passive system, the practical skyhook and the ideal skyhook systems. A simulation study was performed to prove the effectiveness and robustness of the control approach. 