The promoting effect of metal oxides to Pt catalysts toward methanol oxidation reaction (MOR) has attracted widespread attention in recent years. In this communication, we report the promoting effect of MoO3 to Pt catalyst by rationally designing and tuning the nanostructure of the catalysts. MoO3 nanorods are firstly synthesized through hydro thermal method and used as the substrate for the deposition of polyaniline (PANI) layer. The PANI-MoO3 composite nanostructures are then used as the support for Pt catalyst. Depending on the preparation method of Pt nanoparticles, the nanostructure can be PANI nanotube supported Pt (Pt/PANI) through etching MoO3 nanorods with NaBH4 and PANI-MoO3 composite nanorods supported Pt (Pt/PANI-MoO3). The catalytic properties of the two catalysts toward MOR are investigated. Results show that the current of methanol oxidation on Pt/PANI-MoO3 catalyst is comparable to that on Pt/PANI, while the peak potential of MOR on the former is lowered by 180 mV as compared with the latter, suggesting a much higher catalytic activity of Pt/PANI-MoO3. The presence of MoO3 may be responsible for the improvement of the catalytic properties through the co-synergistic effects of PANI and MoO3. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.