Abstract: Failure analysis was carried out for one of a certain type of exhaust pipes used in heavy truck which frequently failed in market. SEM, EDS, metallographic analysis, and hardness tests were performed to find out the failure cause. The results show that the cracking of the brazing joint between flange and strap parts was high-cycle fatigue cracking caused by abnormal vibration. The micro crack initiated from brazing joint between strap and holder and propagated into strap due to resonance. Then other cracks initiated at the brazing joint between flange and pipe and then propagated into pipe body. Coarse grain of pipe body and inadequate hardness of strap near brazing joints were also promoting factors. According to the results, the welding process has been adjusted and vibration reduction treatment has been carried out. As a result, such failure has been effectively prevented.