Abstract: Electro-rheological(ER) fluids have extensive application in the field of vibration control as a kind of intelligent materials.It is very difficult to develop a conventional control system due to the nonlinearity of the ER effect in regard to electric field strength,temperature or shear rate.An adaptive fuzzy control system is composed of a structural identification system and a controller system,and introduced for the ER damper-rotor vibration system due to the function approximator property of fuzzy logical system.A numerical study indicates the validity of the adaptive algorithm and the effective suppresion of the rotor vibration.