Abstract: As the paper drying cylinder is in high temperature, damp and corrosive working environment for a long time,it is easy to produce cracks in the manhole of its end cover, which results in the final fatigue failure. In view of the above situation, the gray cast iron plate was prepared by using casting process. Its microstructure, micro-hardness and tensile strength were tested. In order to simulate the failure form of the end cover of cast iron plate paper drying cylinder, the fatigue test of cast iron plate was carried out, and the evolution process of the structure and phase structure of the cast iron under fatigue condition was studied. The results show that the microstructure of cast iron plates contains a large number of inclusions, which has a serious adverse effect on the mechanical properties of the cast iron. According to the fatigue curve and fatigue fracture morphology, the fracture form of the cast iron sheet can be judged as brittle fracture.