Feedback voltage stabilizing apparatus, method, and power conversion system are disclosed. The apparatus includes a first switching unit, a second switching unit, and a conduction control unit. In which, the first switching unit is coupled to a feedback circuit for controlling whether a feedback signal is transmitted from a first end to a second end. The second switching unit is for avoiding voltage vibrations which caused by the feedback signal occurring at the second end. By capturing a detection signal, the conduction control unit can determine whether to simultaneously turn on the first switching unit and the second switching unit, in order to eliminate the voltage vibrations, or not.