Abstract: In general, the objective of suspension systems of automobiles is to isolate the vibrations produced due to road disturbances from transfer to driver and passengers. The design of a hydraulic control valve to improve the performance of the damper of automobile suspension system is focused in this paper. . The proposed control valve makes the damper of suspension system to behave as a smart damper. A quarter automobile model of two degrees of freedom is adopted.. The parameters of the proposed control valve are optimized according to settling time and peak overshoot. The efficiency of this valve is tested by evaluating the response of the sprung mass when the automobile excited by step and impulse functions. The results show that the smart damper attenuates the vibrations of the sprung mass in a short period when compared with other types of dampers.