The　adsorption　and　decomposition　of　acetonitrile　on　the　SnO2　(110)　surface　were　investigated　by　means　of　first-principles　computations.　It　is　found　that　acetonitrile　could　be　relatively　easier　decomposed　into　CH3　and　CN　fragments　on　the　SnO2　(110)　surface　than　on　TiO2　(110),　which　agrees　with　the　experimental　results.　The　higher　activity　of　the　SnO2　(110)　surface　than　the　TiO2　(110)　surface　can　be　attributed　to　its　higher　work　function　and　closer　molecular　orbital　energies.