MnO2　with　interlayer　Ce3+　cation　(Ce-MnO2)　was　synthesized　by　ion　exchange　approach.　The　Ce-MnO2　exhibited　better　low-temperature　NH3-SCR　catalytic　activity　as　compared　to　Ce0.38Mn0.62O2-CP　prepared　by　co-precipitation.　The　good　performance　was　due　to　easy　supply　of　labile　oxygen　species　generated　by　migration　of　Ce　species　in　Ce-MnO2　catalyst,　which　could　promote　the　oxidation　of　reactants.　The　special　structure　of　Ce-MnO2　promoted　better　properties　in　terms　of　low-temperature　reduction　properties,　lower　element　species,　adsorption　capacity　of　reactants　and　surface　acid　sites,　which　was　beneficial　to　NH3-SCR　at　low-temperature.　It　also　showed　superior　H2O　resistance　with　NOx　conversion　above　90　%　below　150　degrees　C.　The　competitive　adsorptions　between　H2O　and　reactants　over　both　of　Ce-containing　catalysts　were　investigated　by　in-situ　DRIFT　and　TPD.　The　results　indicated　NOx　with　strong　competitive　adsorption　on　Ce-MnO2　surface　than　H2O.　No　competitive　adsorption　between　NH3　and　H2O　over　both　of　Ce-containing　catalysts　was　also　observed,　different　from　previous　reports.