Abstract: A railway turnout switch connecting rod braked after using for less than 3 years, the fracture reasons were analyzed by means of macrograph observing, chemical composition analyzing, metallography examinating, fracture analyzing and hardness testing. The results show that the fracture characteristic was high cycle fatigue fracture. The connecting rod′s cracks originated from stress concentration position, where the connecting rod′s diameter changed and did not treated by induction quenching, and the content of non-metallic inclusions was fair high and the microstructure segregation was found, so that the fatigue strength of the connecting rod decreased. The fatigue cracks extended and caused the connecting rod happening high cycle fatigue fracture under the action of alternating stress.