Vertically oriented TiO2 nanotube (TNT) arrays (TNTs/Ti) of different tube lengths are prepared by anodization process and Pd particles are well dispersed on the TNTs/Ti substrates by pulse electrodeposition technique. Electrochemical measurements show that the conductivity of TNTs/Ti substrate can be largely improved after the deposition of Pd particles and the Pd-TNTs/Ti electrodes show good electrocatalytic activity for ethanol oxidation in alkaline media, which may be ascribed to the well dispersion of Pd particles on the TNTs/Ti substrate, the reduced poisoning on the Pd surface, the high utilization of Pd catalyst and the enhanced direct electron transfer. The Pd particles supported on the TNTs/Ti substrate with the smallest tube length exhibit the best electrocatalytic activity and stability for ethanol oxidation, which may result from the smallest transport resistance of reactants and products and the highest conductivity for TNTs/Ti substrate with the smallest tube length. (c) 2013 Elsevier Ltd. All rights reserved.