Abstract: Refer to the rotor and supporting structure of small aero-engines,a single-disk rotor system supported on a squeeze MR fluid damper was designed and manufactured.The unbalance response of the system at different control currents was experimentally studied.It was found that the effects of the magnetic pulling force on the first critical speed and the amplitude can be omitted.The oil film reaction force can diminish the amplitude at the critical speeds without damper,and increase the critical speeds.The damper will have the best effect in minimizing the vibration within the specified range at all working speed by using on-off control method.The research shows that the squeeze MR fluid damper has the advantages such as structure simplicity,high effectiveness,quick response,etc.,and this kind of damper has a promising potential future in vibration control of high-speed flexible rotor systems.