Abstract: The decomposition of hercynite through oxidation roasting is significant for the subsequent alumina extraction by Bayer process. In this work, the non-isothermal oxidation kinetics of hercynite was studied and the oxidation mechanism was investigated through the analysis methods of X-ray diffraction and X-ray photoelectron spectroscopy. The results showed that hercynite oxidation at 650～900 K and 900～1100 K was respectively controlled by chemical reaction and internal diffusion, and the corresponding reaction activation energies were 59.36 kJ/mol and 20.69 kJ/mol. Hercynite was firstly oxidized into Fe₃O₄ and γ-Al₂O₃, elevated temperature promoted the oxidation of Fe₃O₄ into γ-Fe₂O₃ and further into α-Fe₂O₃, meanwhile γ-Al₂O₃ was transformed into α-Al₂O₃. The migration of iron oxides to particle surface was prior to that of alumina in hercynite, thereby hindering the oxidation of particle interior. This study lays the foundation for the simultaneous oxidation of hercynite during cooling process.