A　series　of　Mn-CeOx(LCS)　catalysts　with　different　molar　ratios　of　metal　nitrates　to　citric　acid　were　prepared　by　low-temperature　combustion　synthesis　(LCS)　method.　Through　a　comparison　with　the　Mn-CeOx(CP)　catalysts　prepared　by　coprecipitation　method　(CP)　as　well　as　various　characterization　techniques　such　as　XRD,　XPS,　FESEM,　H2-TPR　and　nitrogen　physisorption,　the　catalytic　performance　of　Mn-CeOx(LCS)　in　the　selective　catalytic　reduction　(SCR)　of　NOx　by　NH3　was　then　investigated.　The　results　show　that　the　molar　ratio　of　metal　nitrate　to　citric　acid　is　an　important　factor　affecting　the　denitrification　performance　of　the　Mn-CeOx(LCS)　catalysts.　In　comparison　with　the　Mn-CeOx(CP)　catalysts,　the　Mn-CeOx(LCS)　catalysts　are　provided　with　a　higher　manganese　content　and　high　Oα/(Oα+Oβ)　ratio　on　the　surface　as　well　as　more　hierarchical　pores　favorable　for　adsorption　and　reaction　of　reactants,　which　affords　the　Mn-CeOx(LCS)　catalysts　much　better　denitrification　performance.　Over　the　Mn-CeOx(LCS)　catalyst　with　a　molar　ratio　of　metal　nitrate　to　citric　acid　of　36:22,　the　denitrification　rate　at　80-180　reaches　75%-100%;　even　in　the　presence　of　SO2,　the　denitrification　rate　over　the　Mn-CeOx(LCS)　catalyst　at　180　keeps　at　the　level　of　74%.　©　2019,　Science　Press.　All　right　reserved.