Pt catalysts supported on carbon nanotubes (CNT), activated carbon and gamma-Al2O3 were prepared by the electroless plating method. For comparison, the CNT supported Pt was also prepared by the traditional impregnation-reduction method. The physical properties, structure, morphology and Pt loadings of the different catalysts were characterized by BET, XRD, TEM and ICP, respectively. The catalytic activity for HI decomposition was investigated in a fixed bed reactor under atmospheric pressure. The results of XRD and the activity evaluation indicated that the Pt/CNT prepared by the electroless plating method had better catalytic performance than that prepared by the impregnation-reduction method. Among the three kinds of supported Pt catalysts by the electroless plating method, the CNT supported Pt catalyst not only showed the highest activity for HI decomposition, but also had the best stability in specific surface area, structure and morphology. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.