The invention discloses a current control device, a magnetic suspension system and a current control method thereof. The device comprises a displacement comparing unit and a frequency converter insidea motor control system, wherein the displacement comparing unit is arranged between the motor control system of a magnetic suspension system to be controlled and a bearing control system, and is usedfor determining whether the suspension displacement of a rotating shaft inside the bearing control system is greater than or equal to a set value; and the frequency converter is used for controllingthe open-loop starting current of the motor inside the motor control system to be reduced under the condition that the suspension displacement is greater than or equal to the set value. Through the scheme, the problem that the reliability of magnetic suspension is influenced by bearing protection caused by overhigh open-loop starting current can be solved, and the effect of improving the reliability of magnetic suspension is reached.