In this paper, the high-temperature oxidation resistance of Fe-Al-Cr high-aluminium steel with different alloying elements (Si, V) was tested by high-temperature oxidation test at 900℃ for 10 h. The high-temperature oxidation resistance of Fe-Al-Cr-Si was better than that of Fe-Al-Cr and Fe-Al-Cr-V alloys. Experiments revealed that the dynamic process of oxide formation, shedding and matrix oxidation occurs in Fe-Al-Cr alloy in a high-temperature environment. The high-temperature oxidation resistance of Fe-Al-Cr alloy mainly depends on the bonding strength of Fe/Al₂O₃ interface, rather than the positive correlation with the content of Al. The effect of alloying elements on interfacial bonding energy of metal/oxide was calculated by density functional theory. The mechanism of the effect of Si and V on high-temperature oxidation resistance of Fe-Al-Cr alloys was explained. The interfacial bonding force of Fe/Al₂O₃ comes from the covalent effect of Fe-O, and Si can reduce the interfacial bonding energy from-7.16 eV to -7.41 eV, which makes the bonding between Al₂O₃ and matrix more closely. V can increase the interfacial bonding energy to -6.06 eV, which will make the interface easy to fail, lead to the fall off of Al₂O₃, and destroy the high temperature oxidation resistance of the alloy.