As　the　selective　non-catalytic　reduction　denitration(SNCR　denitration)　was　used　in　cement　decomposition　furnaces　under　the　high　concentration　cement　raw　materials　and　complex　flue　gas　composition,　the　denitration　efficiency　is　poor　and　the　reducing　agent　is　largely　consumed.In　order　to　meet　the　more　stricter　requirements　of　environmental　protection,　there　is　an　urgent　need　to　improve　the　denitration　efficiency　of　SNCR　and　reduce　the　escape　of　reducing　agentsin　order　to　prevent　the　unnecessary　waste　caused　by　excessive　use　of　reducing　agents　and　secondary　atmospheric　pollution.Therefore,　studying　the　effect　of　cement　raw　materials　and　O2　concentration　on　SNCR　process　is　very　important.　In　this　paper,　the　initial　concentration　of　NO　and　the　ammonium　to　nitrogen　ration　(CNH3/CNO)　was　800ppm　and　1.5,　respectively.　The　effects　of　cement　raw　material　and　oxygen　concentration　on　the　reaction　process　of　NH3　+NO+O2　in　the　temperature　range　of　750-1100　were　investigated　by　means　of　denitration　rate,　in　Situ　DRIFTS　analysis.The　results　demonstrate　when　O2　concentration　was　5%　and　denitration　temperature　was　950,　the　deNOx　rate　reached　a　maximum　of　89.64%,　which　due　to　O2　promoted　NH3　and　NO　to　react　with　O2　to　produce　N2　and　H2　O.　However,under　the　effect　of　cement　raw　material,　O2　can　promote　NH3　which　was　adsorbed　on　the　surface　of　cement　raw　material　to　react　with　O2　and　produce　NO　and　H2　O,　and　the　reaction　of　oxidation　of　NH3　is　dominant,　therefore,　the　denitration　reaction　is　inhibited..When　O2　concentration　was　5%　and　temperature　was　850,　the　deNOx　rate　reached　a　minimum　value　of　-109.09%.　the　high　concentration　cement　raw　material　and　flue　gas　composition　reduce　the　denitration　efficiency　of　cement　kiln.　©　2018　Trans　Tech　Publications,　Switzerland.