The composites of carbon quantum dots decorated by Pt nanoparticles have been prepared via reduction of carbon quantum dots and H2PtCl6 by sodium borohydride in one pot and the electrochemical activity for methanol oxidation was investigated. Experimental results demonstrate that, in comparison to the widely-used Pt-C catalyst, carbon quantum dot-supported Pt nanoparticles demonstrate enhanced efficiency for methanol electro-oxidation. For instance, by comparison the cyclic voltammofram of Pt-CQD catalyst in acid media and presence methanol observed that active surface area enhanced by increasing methanol, while Pt-C catalyst performance is not like that [1, 2]. Second experiment was investigation effect of the number cycles on ratio of forward peak current density to the backward peak current density of methanol oxidation. Results show that, this ratio increases by increasing the number of cycles. The other work was investigation of effect of increasing of scan rate on oxidation of methanol. Results show that, increases of scan rate can help to improving performance of electocatalyst toward methanol oxidation