Abstract: High temperature smooth persistence, notch cycle persistence and grain size of GH4169G deformed superalloy high pressure baffle forgings for an engine do not meet the technical requirements. In order to find out the reason of unqualified microstructure and properties of forgings,the size of the specimen with unqualified notch cycle persistence of a batch of rear baffles was detected and analyzed, and the high-magnification microstructure near fracture surface of unqualified specimen was detected. The high-power microstructure of forgings with full section was detected and analyzed. The results show that the notched cyclic rupture properties of GH4169G alloy are very sensitive to the notch, and the notch radius has a great influence on the properties,the small notch radius of the specimen is the main reason for the non-conformity of the notch cycle persistence of the forgings. In the high-pressure rear baffle forgings, deformed mixed crystal structure exists locally, and δ phase of large grain boundary is depleted, which is the reason of unqualified high temperature durability.