Abstract: The Co3O4/MPS catalyst was prepared by impregnating Co3O4 on MPS and characterized by XRD and BET. MPS was prepared by the micro emulsion method. The influences of Co3O4 loading, calcination temperature, space velocity, reaction temperature, inlet concentration of NO and volume fraction of oxygen on the performance of catalytic oxidation were examined. The results showed that the surface area of MPS was the largest in three catalyst carriers and Co3O4 was cubic crystal. 25%Co3O4/MPS catalyst calcined at 300℃ for 3h had the smallest crystal particles, the best surface dispersion and optimal catalytic oxidation activity. When the inlet concentration of NO was 500 μL/L, O2 10%, space velocity 12000 h-1, the oxidation rate of NO over Co3O4/MPS reached 50%—60% at 250℃, and the highest absorption efficiency was achieved. At 300℃, the oxidation rate was above 80%, almost equal to the thermodynamic equilibrium value.