The Mossbauer spectra of natural megacrystal clinopyroxene are usually fitted by 4 sets of symmetric doublets, A-A’, B-B’, C-C’ and D-D’, respectively, in terms of increasing Qs value in literature. But the assignments of those doublets are quite different, except the D-D’ doublet assigned to Fe3+ at the lattice site Ml in previous papers. Particularly, the assignment and interpretation of the C-C’ doublet are diverse.The oxidation experiments of natural megacrystal clinopyroxene collected from the Hannuoba basalt, North China, were performed under controlled conditions of temperature at 1000℃ and oxygen fugacity of FMQ buffer in 1, 2, 3 and 5 days respectively. The oxidized samples were then measured by X-ray diffraction spectrometry and Mossbauer spectrometry. The oxidation of clinopyroxene is characterized by Fe2+→ Fe3+ at Ml under the subsolidus conditions, which is consistent with the increase of the area of the D-D’ doublet when the heating time increases. Accordingly, the area of the A-A’ and B The Mossbauer spectra of natural megacrystal clinopyroxene are usually fitted by 4 sets of symmetric doublets, A-A ’, B-B’, CC ’and D-D’, respectively, in terms of increasing Qs value in literature. But the assignments of those doublets are quite different, except the DD ’doublet assigned to Fe3 + at the lattice site Ml in previous papers. Particularly, the assignment and interpretation of the CC’ doublet are diverse. These oxidation experiments of natural megacrystal clinopyroxene collected from the Hannuoba basalt, North China, were performed under controlled conditions of temperature at 1000 ° C and oxygen fugacity of FMQ buffer in 1, 2, 3 and 5 days respectively. The oxidized samples were then measured by X-ray diffraction spectrometry and Mossbauer spectrometry. The oxidation of clinopyroxene is characterized by Fe2 + → Fe3 + at Ml under the subsolidus conditions, which is consistent with the increase of the area of ​​the DD ’doublet when the heating time increases. ea of ​​the A-A ’and B