Generally speaking, due to the excitation of the road and the engine, the fracture of exhaust system often occurs and affects the NVH index of the vehicle. In this paper, through the establishment of structural model of bellows and dynamic model of rubber pendants, the key components and main parameters, which have the biggest influence on vibration characteristics, are determined. Finally, take the fracture fault of a manifold catalytic converter as an example, low cycle fatigue and thermal fatigue analysis are carried out based on CAE and the improvement scheme has been put forward. In addition, the exhaust system of the vehicle is analyzed by modal analysis, the original suspension point position could be modified according to the analysis results. The results show that the fracture fault has been solved and the vibration characteristics of the exhaust system have been optimized.