A　coaxial　dielectric　barrier　discharge　(DBD)　reactor　has　been　developed　for　plasma　and　plasma-catalytic　conversion　of　dilute　N2O　in　N-2　and　N-2-O-2　mixtures　at　both　room　and　high　temperature　(300　degrees　C).　The　effects　of　catalyst　introduction,　O-2　content　and　inlet　N2O　concentration　on　N2O　conversion　and　the　mechanism　involved　in　the　conversion　of　N2O　have　been　investigated.　The　results　show　that　N2O　in　N-2　could　be　effectively　decomposed　to　N-2　and　O-2　by　plasma　and　plasma-catalytic　processes　at　both　room　and　high　temperature,　with　much　higher　decomposition　efficiency　at　300　degrees　C　than　at　room　temperature　for　the　same　discharge　power.　Under　an　N-2-O-2　atmosphere,　however,　N2O　could　be　removed　only　at　high　temperature,　producing　not　only　N-2　and　O-2　but　also　NO　and　NO2.　Production　and　conversion　of　N2O　occur　simultaneously　during　the　plasma　and　plasma-catalytic　processing　of　N2O　in　a　N-2-O-2　mixture,　with　production　and　conversion　being　the　dominant　processes　at　room　and　high　temperature,　respectively.　N2O　conversion　increases　with　the　increase　of　discharge　power　and　decreases　with　the　increase　of　O-2　content.　Increasing　the　inlet　N2O　concentration　from　100　to　400　ppm　decreases　the　conversion　of　N2O　under　an　N-2　atmosphere　but　increases　that　under　an　N-2-O-2　atmosphere.　Concentrating　N2O　in　the　N-2-O-2　mixture　could　alleviate　the　negative　influence　of　O-2　by　increasing　the　involvement　of　plasma　reactive　species　(e.g.,　N-2(A(3)Sigma(+)(u))　and　O(D-1))　in　N2O　conversion.　Packing　the　discharge　zone　with　a　RuO2/Al2O3　catalyst　significantly　enhances　the　conversion　of　N2O　and　improves　the　selectivity　of　N2O　decomposition　under　an　N-2-O-2　atmosphere,　revealing　the　synergy　of　plasma　and　catalyst　in　promoting　N2O　conversion,　especially　its　decomposition　to　N-2　and　O-2.