Abstract: After a certain type of aero-engine worked for 570-600 h, five times of cracking fault happened in it′s compressor rectifier guide vane made of TC11. Using macrography and micrography, fracture analysis, chemical analysis and mechanical property test, the cracking mechanism and causes were determined, and the corrective measures were also put forward. The results show that the crack in the failed vane was fatigue crack whose initial stress and propagation stress were small. Occurrence of the fatigue cracking was not related to the material. The stress concentration in the crack origin area, including assembly stress and resonance stress generated during the engine running, was the main reason of fatigue cracking. Rounding the edge and controlling assembly space in the process can delay fatigue crack initiation.