The　studies　of　NO　chemisorption　on　TiO2(110)　surface　are　the　base　of　research　to　NO　decomposed　to　N2O　on　TiO2　surface.　In　this　paper,　12　kinds　of　possible　models　of　NO　adsorbed　on　TiO2　perfect　and　defect　surface　were　calculated　by　use　of　ab　initio　cluster　method.　We　carried　out　optimization　of　the　geometry,　calculation　of　the　chemisorption　energy　and　analysis　of　the　Mulliken　population　to　those　adsorption　models.　According　to　the　calculation　results,　it　can　be　got　that　the　adsorbed　decomposition　of　NO　on　defect　surface　is　more　advantageous　and　M6　and　M12　are　the　important　models　to　NO　chemisorption　and　decomposition　on　TiO2　surface.