Abstract: Due to the absence of side reactions during the reaction process, carbon monoxide (CO) oxidation, as a typical heterogeneous catalytic reaction model to study the surface redox properties of catalysts, has been extensively studied. It also has many practical uses in gas purification, especially in the purification of automotive exhaust and removal of CO from H₂ for proton exchange membrane fuel cell (PEMFC). Flame spray pyrolysis (FSP) based on the traditional gas-phase combustion of nano-materials, with the characteristics of no post-processing, low cost and easy to large continuous process, has been widely used in the field of catalyst preparation and application. The method of preparing the coexistence of different noble metals and transition metal oxides, taking advantage of the synergy between the elements to improve the activity of catalysts has become an optimized scheme for many researchers. In this paper, a Pt loading catalytic system was prepared by flame spray pyrolysis, and the activity of Pt/TiO₂ system in CO oxidation was largely enhanced by in situ doping Fe and Mn in the spray flame. The effects of Fe and Mn on the crystal phase, specific surface area (SSA), the size and valence of supported particles, the oxygen species on the surface of the support and the surface reduction performance of the system were investigated by X-ray diffraction (XRD), N₂ adsorption-desorption isotherms, transmission electron microscope (TEM), CO chemisorption, X-ray photoelectron spectroscopy (XPS) and hydrogen temperature programmed reduction (H₂-TPR), respectively. The roles of Fe, Mn in the catalysts on the catalytic reaction were also systematically analyzed. The results showed that the addition of Fe and Mn to the Pt/TiO₂ system lowered the temperature at which CO was completely oxidized by 40℃, especially when Mn was doped in the Pt/TiO₂, the TOFs increased by an order of magnitude, making the activity of catalysts even higher than that of the sample when the same mass ratio of Pt was added. Thus an effective way to improve the catalytic activity and to reduce the cost is proposed.