The valve design of a rear twin tube shock absorber belongs to a light commercial vehicle whose damper characteristics already known has been realized by the help of a computer program called “Dr”, and compared with the actual application results. The program gives user results about the valve parts to get the right target characteristics. After obtaining the necessary parts’ results, the needed damping performance test has been performed by the shock absorber, which has been conflated according to the program. The actual results and target characteristics were compared. ”Dr” program enables the user to select the correct parts to be used in valve system by detecting every effect on target characteristics diagram. By comparing the overall effect of the parts selected, shock absorber valve system is conflated according to the valve components obtained from the computer program.