We report the synthesis and characterization of hollow PtNi nanospheres by chemical successive-reduction method. The results of X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) account for the alloy formation between Pt and Ni and electronic structure change of Pt in the alloy. The prepared nanospheres show a high activity and stability for electrocatalytic oxidation of methanol as compared to the commercial Pt/C catalyst and the co-reduced PtNi nanoparticles. The reasons of the high electrocatalytic activity of the hollow PtNi nanospheres were discussed. (C) 2011 Elsevier B.V. All rights reserved.