In this study,the effects of copper (Cu) additive on the catalytic performance of Ag/SBA-15 in complete soot combustion were investigated.The soot combustion performance of bimetallic Ag-Cu/SBA-15 catalysts was higher than that of monometallic Ag and Cu catalysts.The optimum catalytic performance was acquired with the 5Ag1-Cu0.1/SBA-15 catalyst,on which the soot combustion starts at Tig =225℃ with a T50 =285℃.The temperature for 50％ of soot combustion was lower than that of conventional Ag-based catalysts to more than 50℃ (Aneggi et al.,2009).Physicochemical characterizations of the catalysts indicated that addition of Cu into Ag could form smaller bimetallic Ag-Cu nanolloy particles,downsizing the mean particle size from 3.7 nm in monometallic catalyst to 2.6 nm in bimetallic Ag-Cu catalyst.Further experiments revealed that Ag and Cu species elicited synergistc effects,subsequently increasing the content of surface active oxygen species.As a result,the structure modifications of Ag by the addition of Cu strongly intensified the catalytic performance.