The quasi-ferrite model is proposed and an appropriate PBE exchange functional with the spin density functional theory （SDFT） is selected for the calculation of the relation between magnetic moment and residual stress in ferrite using a quantum mechanics code. The relationship between ferrite magnetism and the carbon content is determined, and then a ferrite interstitial solid solution （ISS） model in a low carbon concentration state is replaced with an a-Fe model in the case of majority magnetic calculation. The band structure of the loaded α-Fe is compared with that of the unloaded a-Fe. The comparison shows that the energy of Fe atomic 3d orbital changes a little, while the energy of electron orbital of iron core below 3d almost keeps un- changed. The relationship between the magnetic moment and the stress appears intermittent due to the Bragg total reflection. The change in the magnetic moment due to lattice mismatch is much larger than that caused by mechanical loading.
