Abstract: In the process of fluorescence penetration detection of a new high pressure turbine disc of certain type of aircraft engine after the first all machine test, several trace displays were found in the second and third teeth of the sealing teeth. The cause and mechanism of the crack were determined by physical and chemical analysis, test and process review, and it provided a theoretical basis for developing the troubleshooting scheme and improved the fluorescence penetration detection technology after crack repair. Finally, the process flow of fluorescent permeation recheck of the disk was optimized.