In this paper, the deposition of Ni-Co alloy coating on Cu substrate was prepared by cyclic voltammetry method. The Ni-Co coating was measured by XRD, SEM and EDS to determine the composition and morphology. The deposition of Ni-Co alloy is anomalous deposition, that is, the ratio of Ni-Co in alloy is not equal to that in the deposition bath. With the increase of cyclic times, the content of Co increases. Polarization curves and AC impedance measurement show that the alloy coating electrodes are more active than the Ni electrode. With the content of Co increase in the alloy coating, the electrocatalytic activities of the alloy coating increase. Heat treatment can also improve the properties of alloy coating for OER. (C) 2004 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.