Nowadays, developing highly efficient, stable and low cost catalysts is generally considered to be the key to solve the drastically increasing of carbon monoxide (CO) emission. In this paper, Cu13-mNim(m = 0, 1, 13) bimetallic clusters have been proposed as new cluster catalysts, and their electronic, chemical properties and CO catalytic oxidation reaction are systematically calculated by DFT theoretical simulation. When an O-2 molecule is adsorbed on the active-site of Cu13-mNim cluster, O-2 molecule decomposing reaction occurs firstly, rather than coad-sorption of O-2 and CO molecule, which is modified the traditional Langmuir - Hinshelwood (LH) mechanism. By analyzing the reaction energy barrier of each step on Cu13-mNim clusters, the rate - determining step is determined as the oxidation reaction between a dissociated oxygen atom and carbon monoxide, which is hindered by a significant activation barrier. In addition, microkinetics simulations predict that Cu12Ni cluster is extremely efficient in catalyzing CO oxidation. Our findings present a rational way for designing heterogeneous catalysts with abundant reactive sites.