Abstract: In order to meet the reliability of aero-engine and ensure the flight safety of helicopter, the welding repair of the crack fault of the IV stage guide is studied.The cracks are observed by scanning electron microscopy and optical microscopy to analyze the root causes of guide vanes failure. The high temperature box furnace is used to conduct properties recovery heat treatment of IV-stage guide vanes. The cracks are repaired by TIG welding. The microstructure, hardness, high temperature strength and thermal shock performance before and after repair are compared and evaluated.The repaired IV-stage guide vanes is installed on the engine for test verification. A large amount of σphase is generated at grain boundary during service, decreases the strength of grain boundary, and finally corrosion cracks are generated. Properties recovery heat treatment can lower the brittleness and improve the weldability of matrix materials. The welded joint of stage Ⅳguide vanes produced by TIG welding meets the standard requirements. The dimensions of stage Ⅳ guide vanes, on which property recovery heat treatment, TIG welding and stabilization treatment were conducted, meet the requirements of engine assembly. No cracks, spalling or other abnormalities were detected after engine test.