Abstract: It is vital important for ensuring reliable and efficient rotating machinery operation to eliminate the vibration of rotor system online. Early in the rotor vibration control, a tentative control force is needed. The force might make the system vibration aggravate or reduce, which depends on the relationship between control force phase and excitation vibration force phase. So, depending on the analytic of the rotor system dynamics and electromagnetic force controllable characteristics, the regional division of the phase of control force was done. And the control model was built and some specific optimization strategy was proposed. The finite element analysis method was used to attain the system theory lagging angle under working speed. The phase value of control is determined and the phase is used as the initial value of optimal parameters, and ensuring the vibration amplitude is not more than the initial fault amplitude of rotor during control. Finally the test equipment was established and the experimental results show the algorithm is effective.