The electrocatalytic activity of the Pt/C electrode for the ethanol oxidation was significantly increased after the electrode being treated with mixed solvent of tetrahydrofuran and acetone. The onset potential of the ethanol oxidation shifted more negative than that at the untreated Pt/C electrode. The peak current of the ethanol oxidation at the treated Pt/C electrode was 2.3 and 3.1 times compared with that at the untreated Pt/C electrode in acidic and neutral solution, respectively. In addition, the treatment of the Pt/C electrode could decrease the adsorption strength of COad, the intermediate of the ethanol oxidation and thus, decrease the poison effect of the COad to the Pt/C electrode.