The invention relates to a method for repairing a plunger of a ship steering engine, in particular to a method for repairing the plunger of the ship steering engine, which is particularly suitable to the repair of the plunger of the ship steering engine for a sea ship. The method sequentially comprises the following steps: preprocessing, spraying, brush plating, bath plating, simulating and examining, and accepting. The invention not only can fully repair the plunger of the ship steering engine to meet total repair requirements, but also can not damage original metallographic structures and base materials of the plunger of the ship steering engine without causing welding distortion, can not increase the processing difficulty of the plunger of the ship steering machine and can not influence the subsequent bath chromium plating process of the plunger of the ship steering engine after the repair, and is convenient for field maintenance.