Abstract: The stainless steel conduit cracked at the position of the fixed clamp band during service. The installation position, structural characteristics and assembly of the fractured conduit were inspected. The cracking cause of the conduit was analyzed in combination with macroscopic observation, fracture surface analysis, chemical analysis, metallographic inspection, and finite element simulation. The results show that the cracking property of the conduit is high-cycle fatigue fracture. The fatigue crack originated from the mechanical damage part outside the conduit. The conduit was subjected to bending vibration load, and the fatigue crack initiated at the stress concentration of the conduit, and then the fatigue propagates. It is recommended that the operation of conduit parts should strictly follow the relevant requirements to avoid mechanical damage caused by abnormal force.