Abstract: By means of macro and micro fracture analysis, chemical composition analysis, metallographic examination and hardness test, the fracture reasons of the slide plate of a metro turnout were analyzed. The results show that the failure mode of the slide plate was fatigue fracture. The coarse grain and lower hardness of the weld seam caused by the improper welding procedure, as well as the stress concentration at root of the weld seam, were main reasons for the fatigue fracture. Finally, the corresponding improvement measures were put forward.