Developing　a　catalyst　with　high　SO2　and　H2O　resistance　to　achieve　high-performance　CO　oxidation　for　specific　industrial　applications　is　highly　desirable.　Here,　three　catalysts　were　prepared　using　cerium　titanium　composite　oxide　(CeTi),　molybdophosphate　with　Keggin　structure-modified　CeTi　(Keg-CeTi),　and　molybdophosphate　without　Keggin　structure-modified　CeTi　(MoP-CeTi)　as　supports,　and　their　sulfur　and　water　resistance　in　CO　oxidation　were　tested.　The　characterization　of　XRD,　BET,　SO2/H2O-DRIFTS,　XPS,　TEM,　SEM,　NH3/SO2-TPD,　H-2-TPR,　and　ICP　techniques　revealed　that　the　high　SO2　and　H2O　resistance　of　Pt/Keg-CeTi　in　CO　oxidation　was　related　to　its　stronger　surface　acidity,　better　reduction　of　surface　cerium　and　molybdenum　species,　and　lower　SO2　adsorption　and　transformation　compared　to　Pt/CeTi　and　Pt/MoP-CeTi.