Carbon monoxide (CO) is a common air pollutant in industrial flue gas and motor vehicle exhaust, and its excessive emissions pose a serious threat to human health. Currently, catalytic oxidation technology is widely used for CO emission control. However, sulfur dioxide (SO_2), which is prevalent in industrial flue gas and motor vehicle exhaust, can cause irreversible poisoning of CO oxidation catalysts, resulting in their severe deactivation. Therefore, improving the SO_2 resistance performance of CO oxidation catalysts has become a research hotspot in the field of environmental catalysis. This review summarizes the SO_2 poisoning mechanism on CO oxidation catalysts, categorizes the methods of characterizing sulfur species on the catalyst surface, and discusses effective strategies to enhance the SO_2 resistance performance of various CO oxidation catalysts. This review will contribute to the understanding of the adsorption and transformation processes of SO_2 on the catalyst surface, revealing the mechanism of the interaction between SO_2 and catalysts, and providing significant references for the design and synthesis of CO oxidation catalysts with superior SO_2 resistance performance.