Platinum nanoparticles were electrodeposited on ordered silicon nanocones (SNCs) and used as the catalyst for methanol electro-oxidation in direct methanol fuel cells (DMFCs). Because of uniform dispersion of Pt nanoparticles and the high surface area, the Pt-SNC electrode exhibited superior electrocatalytic properties toward the methanol electro-oxidation, with the onset potential of 0.08V (vs. SCE). According to chronoamperometric analysis and CO stripping cyclic voltammetric (CV) study, the Pt/SNC electrode had a stable electro-oxidation activity with a very good CO tolerance. The Si surface oxide surrounding the Pt nanoparticles on the SNCs was suggested to play a key role in improving the CO tolerance via the bifunctional mechanism.