A quarter - car suspension system in which the MR fluid dampers are used as the semi - active control actuators has been proposed and developed based on the theory analysis of MR fluid dampers characteristic. A adaptive fuzzy logic controller is developed. The completed system is simulated via SIMULINK Toolbox of MATLAB 6.1. Compared to the passive suspension system and simple fuzzy logic controller, the adaptive fuzzy logic controller markedly reduces the vertical acceleration of the sprung mass and effectively improves ride comfort of automobile.