The　adsorption　behavior　of　NOonto　a　Cu3Pt(111)　surface　was　studied　using　a　periodic　slab　model　and　the　PW91　generalized　gradient　approximation　(GGA)　within　the　framework　of　density　functional　theory.　The　calculated　results　indicated　that　NO　adsorption　with　N-down　on　the　top-Pt,　hcp1,　and　fcc2　sites　resulted　in　favorable　structures　with　predicted　adsorption　energies　of　101.8,　124.5,　and　118.1　kJ.mol(-1),　respectively.　For　adsorption　onto　the　hcp1　and　fcc2　sites,　N　atom　from　NO　formed　bonds　with　Cu2Pt　and　Cu-3　clusters,　respectively.　An　analysis　of　the　density　of　states,　charge　population,　and　vibrational　frequencies　before　and　after　the　adsorption　showed　that　electrons　transferred　from　the　surface　of　the　alloy　to　NO　and　that　the　N-O　bond　was　elongated　and　its　vibrational　frequency　was　red-shifted.　The　Cu3Pt　alloy　and　pure　precious　metal　Pt　have　similar　adsorption　properties　to　NO.