A　series　of　CuFe　and　Ag-modified　CuFe　composite　catalysts　were　prepared　for　low-temperature　selective　catalytic　oxidation　of　ammonia　(NH3-SCO).　Significant　synergistic　effects　existed　between　Cu　and　Fe　oxides　in　the　CuFe　(7:12)　catalyst　for　catalyzing　NH3　oxidation.　Loading　6　wt.%　Ag　over　CuFe(7:12)　further　enhanced　NH3　conversion　and　N2　selectivity.　At　200　degrees　C,　NH3　conversion　and　N2　selectivity　reached　97.1　%　and　79.3　%,　respectively,　over　6Ag/CuFe(7:12).　Besides　the　exceptional　catalytic　effects　of　Ag　species,　the　increased　surface　area,　formation　of　CuFe2O4,　improved　reducibility　of　Cu　and　Fe　oxides,　and　increased　acid　sites　due　to　the　composite　of　Cu　and　Fe　and　modification　with　Ag　contributed　to　the　superior　performance　of　the　6Ag/CuFe(7:12)　catalyst　in　NH3-SCO.　In-situ　DRIFTS　results　showed　that　NH3　oxidation　might　follow　the　internal　selective　catalytic　reduction　mechanism:　NH3　was　dehydrogenated　and　oxidized　to　NOx　and　nitrate　species,　and　the　formed　NOx　and　nitrate　species　were　reduced　by　the　remaining　NH3,　-NH2　and　-NH　species　to　N2　and　H2O.　Loading　Ag　over　CuFe(7:12)　suppressed　the　formation　of　NO　and　NO2　but　promoted　that　of　N2O　during　NH3　oxidation,　which　could　be　attributed　to　the　enhanced　formation　and　decomposition　of　NH4NO3　in　the　presence　of　Ag.