In this paper, size controllable hollow carbon spheres used as catalyst carrier were prepared by hydrothermal synthesis with glucose as the raw material without adding organic template, the self-made flower-like CeO₂ with a pore size in the range of 30nm~40nm and a specific surface area of 126m₂/g was added as auxiliary catalyst, and the catalyst was prepared by microwave-assisted reduction of chloroplatinic acid with ethylene glycol. The prepared catalyst carrier and auxiliary catalyst were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), infrared spectroscopy (IR), X-ray diffraction (XRD) and specific surface area (BET). The electrochemical performance of the prepared catalyst was tested by electrochemical workstation. The results show that the size distribution of the carbon sphere is between 0.4μm and 0.9μm and the surface contains -OH, -C=O, -COOH oxygen-containing functional groups. The results of electrochemical tests show that compared with the traditional Pt/C catalyst, Pt-CeO₂/C catalyst with the addition of flower-like CeO₂ has better catalytic activity, stability and anti-CO poisoning capacity. With the decrease of the size of the carbon sphere carrier, the catalytic performance, stability and anti-CO poisoning ability of the catalyst was enhanced. The catalyst was prepared by the carbon spheres as the carrier which were prepared under the condition of glucose concentration of 0.5mol/L and hydrothermal reaction time of 4h and the floral CeO₂ as the auxiliary catalyst which has the best activity, stability and anti-CO poisoning capacity for the catalytic oxidation of ethanol.