Abstract: The main shaft of a stone cone crusher with 42CrMo material fractured after half a year of service. The failure analysis of the fractured shaft was carried out by means of macroscopic analysis, chemical composition analysis, non-metallic inclusion assessment, macroscopic test, tensile test, impact test, hardness test, average grain size assessment, metallographic examination, microscopic analysis and energy spectrum analysis. The results show that during the operation of the crusher, wear occured between the spindle and the cone core, micro-cracks occured on the outer circumferential surface of the spindle, fatigue fracture of final spindle under cyclic loading.