The　coadsorbed　structures　of　Cu　and　NO　on　perfect　TiO2(110)　surface　were　optimized　and　the　calculation　of　electronic　structure　of　the　most　stable　adsorbed　model　was　performed　by　using　DFT/B3LYP　method.　The　optimized　result　indicates　that　the　Cu　atom　prefers　to　be　bound　on　top　of　bridging　oxygen　and　the　NO　is　adsorbed　on　Cu/TiO2(110)　by　its　O　atom　bridging　two　Cu　atoms.　Cu　adsorption　on　perfect　TiO2(110)　surface　cannot　reduce　surface　Ti4+(5f)　ions　into　Ti3+.　The　DOS　analysis　finds　that　the　Cu　3d　orbitals　appear　in　the　band　gap　of　perfect　TiO2(110)　and　are　the　main　component　of　the　active　surface　state.　The　mechanism　of　the　NO　adsorption　on　the　Cu/TiO2(110)　surface　is　different　from　that　on　Na/TiO2(110).　(c)　2005　Elsevier　B.V.　All　rights　reserved.