Physico-chemical characterization of commercially available Pt/C catalysts before and after methanol oxidation experiments was carried out by X-ray diffraction, scanning electron microscope and transmission electron microscopy. Meanwhile, the electrocatalytic performance of the glassy carbon electrode modified with the carbon supported Pt nanoparticles for the oxidation of methanol has been studied by means of electrochemical method. The experimental results showed that the Pt/C/GC electrode had high electrocatalytic activity for the electrocatalytic oxidation of methanol. The electrochemical reduction of the Pt oxide is inhibited owing to the strong binding of Pt to the support in the Pt/C catalyst. By means of SEM and cyclic voltammetric studies, it was shown that a surface structure-sensitive effect might exist during electrooxidation of methanol on Pt/C catalyst.