Abstract: The activated carbon supported Pt(Pt/C) and the mixture of the activated carbon and the graphite supported Pt(Pt/CG) catalysts were prepared using chemical reduction method. It was found that the weight ratio of the activated carbon and the graphite could affect the electrocatalytic activity of the Pt/CG catalysts for ethanol oxidation. When the weight ratio of the activated carbon and graphite is 15∶1, the Pt/CG catalyst shows the best electrocatalytic activity for ethanol oxidation. It is mainly attributed to the high dispersion of the precipitated Pt particles and the large electrochemically active area when the weight ratio of the activated carbon and the graphite is suitable. In addition, the addition of graphite would increase the conductivity of the catalyst.