Driven by increasingly stringent nitrogen oxides (NO) control requirements, and thelimitations of NH-selective catalytic reduction (NH-SCR) technology, CO-selective catalytic reduction(CO-SCR) technology is attracting considerable attention. This technology utilizes the carbon monoxide(CO), naturally present in industrial flue gas from processes like ferrous metallurgy and wasteincineration, as a reducing agent. It selectively reduces NO, simultaneously removing both NO andCO, thereby addressing secondary pollution and high costs while achieving waste utilization forEnergy Environmental Protectionpollution control. This approach offers substantial environmental and economic benefits. Currently,research on CO-SCR technology is receiving considerable attention in the fields of energy conservationand environmental protection. However, research primarily focuses on optimizing catalyst performanceand structure, while the underlying reaction mechanisms in diverse environments remain unclear.Overall, the technology is in its early stages and requires the development of efficient catalysts tailoredfor industrial applications. The development of catalysts for CO-SCR primarily focuses on reducing theuse of precious metals while enhancing the simultaneous removal of NO and CO. Synergistic effectscan be achieved through methods such as doping with transitional metals like copper (Cu), manganese(Mn), and iron (Fe), or by selecting suitable carriers and innovative structural designs. Furthermore,maintaining high activity in complex environments is critical for practical applications. Factors such asoxygen-rich conditions, water vapor (HO), sulfur dioxide (SO), and alkali metal poisoning cansignificantly affect catalytic performance. Investigating the deactivation process through simulations ofindustrial flue gas and in situ characterization techniques is crucial for understanding catalyst resistanceto poisoning. This review elucidates the fundamental reaction processes of CO-SCR and the challengesof its practical application. It provides a detailed summary of the performance advantages andfabrication methods of three catalyst types currently under investigation. These include precious metalcatalysts, metal oxide catalysts, and molecular sieve catalysts. It also analyzes the reaction mechanismsand approaches for mitigating catalyst poisoning under different reaction conditions, such as oxygen-rich, water-containing, sulfur-containing, and various complex environments. Furthermore, it presentsprospects for the future development of CO-SCR catalysts. This research offers theoretical guidance fordeveloping more efficient industrial catalysts for simultaneous pollutant removal.