Abstract: The connecting rod cracking and fracture phenomenon occurs frequently in the heating furnace in the step beam lifting work process. Its fault reason and fracture mechanism were analyzed. The patch test for the heating furnace connecting rod of walking beam under the service condition was carried out and the full load service during the process after change of the force was obtained. According to the test data and the statistical data of the history of the machine factory production of steel varieties,the load spectrum of the rod was made to complete the analysis of fatigue. The calculation results show that the service furnace satisfies the fatigue life of the design,and the fracture is due to the additional bending moment of the hinged bearing of the synchronous shaft,which results in the increase of the additional bending moment of the connecting rod. The hinge bearing stress state can be improved by improving the lubrication condition of connecting rod. Meanwhile,the ability of the bending deformation of the connecting rod can be significantly increased by the reinforcing plates near the connecting rod.