Abstract: The corrosion resistance of Zr-0.8 Sn-1 Nb-0.3 Fe alloys prepared by two different processes was investigated in 400℃/18.6 MPa superheated steam by static autoclave after irradiated by 360℃ with Kr⁺-irradiation of 5~25 dpa. The microstructures of oxidation film after corrosion were analyzed by TEM, SEM, and XRD. The results showed that the corrosion weight-gain increased with the irradiation dose, while the weight-gain of 1# alloy with smaller and more dispersive SPPs than 2# alloy was lower under the same irradiation dose. Before corrosion turning, the oxygen content in the oxidation film decreased from the steam-side to the zirconium matrix. The oxidation film beside the steam-side was mainly composed by equiaxied monoclinic ZrO₂ crystal, while near the film/matrix interface by columnar quartet ZrO₂ crystal and hexagonal Zr₃O crystal. After transition of corrosion weight, the film near the interface grew like cauliflowers, and the size of cauliflowers were corresponded to the growth rate and uneven growth trend of oxidation film.