Au/SnO2　catalysts　were　prepared　by　deposition-precipitation　(DP),　co-precipitation　(CP)　and　typical　wet　impregnation　methods　(IM).　M(M=　Pt,　Pd)-promoted　Au/SnO2　catalysts　were　prepared　by　the　DP　method.　The　samples　were　characterized　by　X-ray　diffraction　(XRD),　Brunaner-Emmett-Teller　(BET)　adsorption,　transmission　electron　microscopy　(TEM),　and　X-ray　photoelectron　spectroscopy　(XPS)　techniques.　The　results　showed　that　compared　with　CP　and　IM,　the　DP　method　led　to　a　fairly　uniform　dispersion　of　gold　nanoparticles　with　diameters　less　than　5　nm　and　larger　specific　surfaces　for　the　Au/SnO2　catalyst.　The　Au　in　Au/SnO2-DP　was　metallic　(Au-0)　while　in　Au/SnO2-CP　and　Au/SnO2-IM　the　Au　consisted　of　a　mixture　of　Au-0　and　Au3+.　The　oxidation　of　carbon　monoxide　over　the　Au/SnO2-DP　and　M-promoted　Au/SnO2-DP　catalysts　were　investigated.　We　observed　that　the　Pd-　or　Pt-doping　of　Au/SnO2-DP　resulted　in　a　significant　increase　in　performance.　We　conclude　that　the　different　activities　of　the　Au/SnO2　catalysts　that　were　prepared　using　different　preparation　methods　may　be　attributed　to　the　size　of　the　Au　particles　and　the　states　of　gold.　A　remarkable　improvement　in　catalytic　activity　because　of　Pd　or　Pt　doping　was　associated　with　strong　interactions　between　Pd　or　Pt　and　Au.