A fast search algorithm of phase is proposed. In particular plane of rotor, the electromagnetic device is used to generate rotating vector force, of which amplitude and phase can be controlled, to compensate the synchronous unbalancing force of rotor system. In this way, single plane rotor system synchronous vibration fault is eliminated online. Rotor synchronous vibration and electromagnetic controllable characteristics are analyzed firstly, and then, theoretical analysis on the rotor system is done also. Based on these analyses, an optimal control model is designed, in which rotor vibration response is regarded as control target and the amplitude and phase of coil current are regarded as optimal parameters. As a result, complete period search algorithm and fast search algorithm of current phase are proposed. At last the test equipment is established for experimental study. When the rotor is working at 2100r／min, the results of synchronous vibration suppression show that, using complete period search algorithm, the decline in vibration 90％ need 20 seconds, and using fast search algorithm in 4 seconds can achieve the same effect. Obviously, the fast search algorithm of phase greatly improves the rotor vibration fault self-recovery regulation efficiency.