The characteristics of CO and NO adsorption on (110) surfaces of Cu (modeled by Cu-14 cluster) and its alloys containing Ni (modeled by Cu13Ni and Cu12Ni2 clusters) bonded with the C and N atom, respectively, have been studied by using the Self-Consistent-Charge Discrete Variational Method (SCC-DVM). The order of the chemisorption potential of these six adsorbed systems are: Cu13Ni-NO > Cu13Ni-CO > Cu12Ni2-NO > Cu-14-NO > Cu12Ni2-CO > Cu-14-CO. The adsorption selectivities of CO and NO on the (110) surface of copper and its alloy containing Ni are discussed by analysis of the potential curve, density of states (DOS), bonding characters and the electron transfers.