The　loaded　modes　of　NiFeB2　supported　on　the　TiO2(110)　surface　were　studied　with　a　periodic　slab　model　by　PW91　approach　of　GGA　within　the　framework　of　density　functional　theory.　The　results　of　geometry　optimization　indicated　that　the　most　stable　adsorption　site　was　NiFeB2　cluster　parallel　to　the　Ot-Ot　site　with　an　adsorption　energy　of　526.4　kJ/mol.　In　order　to　investigate　whether　the　NiFeB2/TiO2　had　the　catalytic　activity　for　CO　oxidation,　the　co-adsorption　of　CO　and　O2　molecules　on　NiFeB2/TiO2　surface　was　studied.　The　results　showed　that　the　CO　and　O2　were　co-adsorbed　on　the　Fe　site　by　the　Eley-Rideal　mechanism　to　form　carbonate.　When　the　CO　and　O2　were　co-adsorbed　on　the　Fe　site　by　the　Langmuir-Hinshelwood　mechanism,　the　oxygen　decomposed　and　bonded　with　Fe,　Ni,　and　B　atoms,　forming　a　stable　six-membered　ring.