Abstract: The chemical composition, tensile strength, metallography and the surface corrosion products of the material of the failure boiler tubers were tested and analyzed. Experiment results were showed that the oxidation and decarbonization, tensile strength decrease, grain size augmentation and pearlite sphericalization of the failure tubers were severe. Based on above comprehensive analysis, it was the abnormal over-temperature operation that resulted in the failure of boiler tubers.