CuO-CeO₂ is taken as the active component and mullite as the carrier, the Cu-Ce monolithic catalyst is prepared by impregnation method for CO catalytic oxidation of actual sintering gas. The catalytic performance is tested under different preparation methods and reaction conditions, and the conversion rate of CO reaches 93% when the active components are impregnated at the same time, the impregnation solution concentration is 2 mol/L, and the reaction conditions are 180 °C and 4 500 h^-1. After 200 h of catalysis, the catalytic efficiency can still reach more than 90%. At the reaction temperature of 180 °C, the catalyst exhibits different stability under the conditions of SO₂, H₂O, and H₂O and SO₂ could significantly inhibit the catalytic performance of the catalyst, and the inhibition effect of SO₂ is more obvious. The introduction of H₂O covers the active site on the surface of the catalyst, inhibiting the adsorption of CO and O₂, resulting in a decrease in catalytic efficiency. The introduction of SO₂ leads to the accumulation of SO₄^2- species on the surface of the catalyst, thereby inhibiting the catalytic oxidation of CO, resulting in irreversible inactivation of the catalyst. At the same time, a batch of 1 m³ monolithic catalyst is prepared for the pilot test of CO purification of sintering gas. In the pilot test lasting 720 h, the temperature of the imported gas is about 200 ~ 220 °C, the average gas temperature of the outlet is about 240 °C, the CO catalytic efficiency is greater than 70% (the average is 73%), and the mass concentration of CO at the outlet is about 1 700 mg/m³.