Abstract: In order to analyze the reason for fracture of afterburner igniter nozzle tube,the means,such as characters of fracture,X-ray energy analysis,trace analysis and microstructure examination,were conducted. The results showed that the afterburner igniter nozzle tube failed due to high cycle fatigue fracture with high original stress,and fatigue crack started from welding zone between afterburner igniter nozzle tube and afterburner fuel manifold. The main cause of fatigue origination was excessive assembly stress which was created in the course of heavy repair assembly,and the issue of missed check also existed.