Abstract: As one of the typical heterogeneous catalysts, the supported noble metal materials (e.g. Pt, Au, Pd, etc.) with exceptional catalytic performance are widely used for catalytic applications. Besides control and design of the nanostructure, the synthesis approach is crucial for catalytic materials with outstanding chemical and physical properties. Today, most laboratory preparation even industrials manufacturing of catalysts is based on wet-phase techniques:co-precipitation, deposition-precipitation, colloid precipitation, incipient wetness impregnation and so on. Compared to conventional techniques, flame technology with scalable, continuous and well-established advantages is an effective method for the production of supported noble metal catalysts in large quantities and low cost. Especially, with versatile liquid precursors, flame spray pyrolysis (FSP) technique shows a considerable potential for one-step and bottom-up synthesis of nanocatalysts with complex components and structure. Due to high flame temperature, the fast quenching rate, unique sintering and growth process in flame, strong metal-support interaction and high dispersion for loadings are realized. In this paper, a series of Pt/Ti_xCe_(1-x)O₂ nanoparticles were prepared by flame spray pyrolysis using titanium isopropoxide, cerium 2-ethyl hexanoate and chloroplatinic acid dissolved in propionic acid as precursors. The influence of the amount of CeO₂ on particles size, crystal form, the oxygen vacancy of surface and the catalytic activity for CO oxidation was systematically studied. Meanwhile, the growth mechanism of nanoparticles in the flame spray pyrolysis process was discussed. According to results, the cerium can incorporate into titania lattice and induce anatase TiO₂ transform to rutile TiO₂. The titanium-doped cubic CeO₂-rich particles grow epitaxially on rutile TiO₂ (101) lattice plane and elongate as islands. The Ce³⁺ increases the oxygen vacancies of particles surface and promotes the possibility of active oxygen to involve in CO catalytic oxidation. Pt/Ti_0.9Ce_0.1O₂ exhibits the best CO catalytic oxidation performance and up to 100% CO conversion at 70℃.