The　yCe-xMn/Fe-PILC　(x　and　y　are　the　nominal　weight　percentages　of　Mn　and　Ce,　respectively;　x　=　4.0　wt%,　y　=　2.0,　4.0,　and　6.0　wt%)　catalysts　were　prepared　using　the　impregnation　method.　Physicochemical　properties　of　the　as-prepared　materials　were　measured　by　means　of　the　XRD,　SEM,　BET,　TPR,　XPS,　TGA-DSC,　and　in　situ　DRIFTS　techniques,　and　their　catalytic　activities　for　the　selective　catalytic　reduction　of　NO　with　NH3　(NH3-SCR)　at　low　temperatures　were　evaluated.　The　4Ce-4Mn/Fe-PILC　showed　the　highest　NO　conversion　of　95%　at　350　degrees　C　and　better　resistance　to　SO2　poisoning　than　the　Ce-free　4Mn/Fe-PILC.　The　loading　of　ceria　not　only　increased　the　concentrations　of　active　Mn4+　species　and　chemisorbed　oxygen　(O-ads)　species,　but　also　improved　redox　ability　of　the　4Ce-4Mn/Fe-PILC.　After　SO2　poisoning,　the　concentrations　of　active　Mn4+　and　O-ads　species　in　the　ceria-loaded　samples　were　decreased　by　less　extents　than　those　in　the　ceria-free　sample.　The　in　situ　DRIFTS　results　further　demonstrated　that　the　doping　of　ceria　increased　the　amount　of　acid　sites,　enhanced　the　formation　of　NH3　intermediates　(i.e.,　monodentate　nitrite　and　bridging　nitrate),　and　protected　the　main　active　Mn4+　species.　Therefore,　the　samples　containing　ceria　possessed　better　resistance　to　SO2　poisoning.