Platinum nanoparticles have been successfully assembled on polyaniline functionalized graphite nanoplatelet (GNP) via a noncovalent functionalization strategy. The characterization of obtained nanocomposite was investigated by XRD, TEM, XPS and electrochemical technology. When the moderate amount of polyaniline as a stabilizer, Pt nanoparticles with sizes of approximate 4-5 nm uniformly disperse on GNP surface. In methanol oxidation reaction, the electrocatalytic activity of Pt/PANI-GNP is nearly 2 times higher than that of Pt/GNP catalyst. Through analysis, it is suggested that the electrocatalysis performance of Pt/PANI-GNP may be improved by the following four factors: (1) uniformly distributed nanoparticle; (2) increased of amount of Pt degrees and oxygen-containing groups; (3) the existence of N atoms; (4) difference reaction mechanism. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.