Abstract: Aiming at vibration problem caused by multiple oscillation sources in the shaft system of tubular hydro-generator set, based on the model of tip impact force composed of linear contact force and Coulomb friction force, considering the external excitation of unbalanced magnetic pull, oil film force and unbalanced hydraulic force, etc., the dynamic model of rotor-runner-bearing system with rub-impact was established. In order to suppress the rubbing fault stemming from vibration of runner blade, a current-regulated magneto-rheological fluid damper was introduced into the system, and the numerical simulation method was used to study the influence for both presence and absence of magneto- rheological fluid damper on inhibition law of runner vibration at different speeds and mass eccentricity of runners. The results show that the existence of magneto-rheological fluid damper makes the originally complex system response form become orderly, which can attenuate the vibration generated by units during the speed change process and make the runner movement closer to synchronous periodic motion form. Meanwhile, it can reduce the corresponding amplitude fluctuation and chaotic behavior caused by the change of mass eccentricity. Magneto-rheological fluid damping passive control has good applicability to the tubular hydro-generator set, which can provide a useful reference for shaft vibration reduction of tubular units.