<p>CO is highly toxic and seriously harmful to human health, so it is meaningful to control CO emissions, especially from industrial plants. Catalytic oxidation is regarded to be an effective method for CO removal, in which Pt-based catalysts show excellent performance. Studies of catalytic CO oxidation employing Pt-based catalysts often encounter challenges such as CO poisoning, challenges in activating O₂, significant temperature sensitivity, and inadequate tolerance to water and sulfur species. These experimental hurdles have been corroborated by density functional theory (DFT) computations, which model adsorption, reaction pathways, and electronic structures at catalyst surfaces. DFT analysis has elucidated the underlying mechanisms behind these limitations, laying the foundation for enhancing the efficacy of Pt-based catalysts within the scope of academic discourse. DFT has been used intensively in recent years to study the reaction mechanism and functioning characteristics of Pt-based catalysts in CO oxidation. Consequently, advancements in research on DFT experiments on Pt-based catalysts are described. This review provides a comprehensive overview and insights into the mechanism of CO adsorption on the surface of single-atom and multi-atom Pt-based catalysts, its effect on CO oxidation performance, and reaction pathways of CO oxidation in the hope of providing theoretical guidance for the structural design of most effective catalysts.</p>