The activity performance of Ag Mn,Ag Co and Ag Ce composite oxides for CO oxidation and CO NO reaction,the reduction and re oxidation properties were investigated.Results show that the activity performance of binary oxide catalysts is higher than that of individual catalysts for both CO oxidation and CO NO reaction.However,for CO NO reaction N 2 selectivity of Ag Mn(4∶1)/Al 2O 3 and Ag Co(4∶1)/Al 2O 3 catalysts is similar to Ag/Al 2O 3 catalyst,combined the properties of reduction and re oxidation,the cooperating action in binary oxide catalysts was also discussed.