Mn-Ni/TiO2　catalysts　were　prepared　using　a　joint　precipitation　method　with　acid-dissolved　titanium　slag　as　raw　material　for　selective　catalytic　reduction　of　nitrogen　oxide.　The　joint　precipitation　method　was　accomplished　with　different　precipitants,　such　as　sodium　hydroxide,　carbamide,　ammonia,　or　hydrogen　peroxide.　The　deNOx　activities　of　the　catalysts　prepared　by　different　precipitants　were　investigated　with　SCR　activity　reactor　within　temperatures　of　90-350　degrees　C.　It　is　evident　that　the　Mn-Ni/TiO2　catalyst　with　carbamide-ammonia-hydrogen　peroxide　as　precipitant　has　superior　catalytic　activity,　which　the　NO　conversion　can　reach　90%　at　120　degrees　C,　with　a　wider　temperature　window　(120-300　degrees　C)　for　the　NH3-SCR　reaction.　H-2-TPR　results　showed　that　the　reduction　potential　of　MnOx　species　on　Mn-Ni/TiO2　catalysts　is　increased　compared　to　that　of　Mn/TiO2　catalysts.　Oxygen　mobility　is　enhanced　by　interaction　between　Ni　and　Mn　atoms　due　to　use　of　carbamide-ammonia　peroxide　as　precipitant.　XPS　results　suggest　that　the　presence　of　MnO2　is　the　major　phase　in　nickel-doped　Mn/TiO2　catalysts.　Our　NH3-TPD　results　illustrated　that　the　catalysts　have　a　lot　of　acid-active　sites,　which　lead　to　attracting　more　ammonia　to　participate　in　the　catalytic　reaction.