We described a facile and eco-friendly method for preparation of Pd nanocomposites (Pd-PDDA/RGO), which possesses a low Pd metal percent (20 wt%) and a mean size of 3.9 nm. The reaction was carried out at room temperature using Pd nanoparticles anchored on reduced graphene oxide (RGO) with the assist of poly(diallyldimethylammonium chloride). The Pd nanoparticles were well distributed without obvious aggregation. The Pd-PDDA/ RGO nanocomposites exhibit higher electrocatalytic activity and stability for the electrooxidation of ethanol than Pd/RGO, Pd-PDDA/MWCNTs (multi-walled carbon nanotubes) and Pd-PDDA/XC-72 carbon black. The peak current density for ethanol oxidation of PdPDDA/RGO is 1.38, 1.60 and 2.40 times stronger than that of Pd/RGO, Pd-PDDA/MWCNTs and Pd/XC-72, respectively. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.