Replacement method of rectifier blade in engine

The invention discloses a replacement method of a rectifier blade in an engine. The replacement method of the rectifier blade in the engine comprises the steps that a machining method is adopted to cut off a replaced blade located on the upper part of a shell body, and then remnants, on the surface of the upper part of the shell body and in a shell body groove, of the replaced blade are cleaned; residual brazing filler metal located on the inner wall is removed by a scraper similar to the blade shape; a new blade is installed in the shell body groove; an inert gas box is installed on the position, located on one side of the new blade, of a non-welded surface of the shell body, and inert gases blown from air outlet holes of the inert gas box at least cover the replaced blade and two adjacent blades of the replaced blade; the other side of the new blade is welded using BAg50Cu brazing filler metal. According to the replacement method of the rectifier blade in the engine, the reverse sideof welding is protected