Abstract: The interstitial defect model of Cr₂O₃ crystal was established by VASP program, using first-principles calculations based on density functional theory. The Cr₂O₃ crystal structure with Cr atom occupying different interstitial positions was optimized, and the diffusion pathways and energy barriers of interstitial Cr atom in different orientations were calculated and analyzed in combination with NEB (nudged elastic band) method. The results show that the most stable interstitial position of Cr atoms in the Cr₂O₃ crystal is the center of the oxygen octahedral interstitial. The diffusion energy barriers of Cr atom in the directions of 110, 100, and 001 are 1.03 eV, 2.22 eV and 7.68 eV, respectively. Our results reveal the orientation of Cr diffusion in Cr₂O₃ crystals, which can provide theoretical guidance for related experiments and improve the application of ferritic alloy interconnect in solid oxide fuel cells.