Dynamic cyclic voltammetry is performed as functions of cycle number and potential window for the electrodeposition of Pt-Ru-Co and Pt-Ru-Ni catalysts on a carbon fiber (CF) web. Surface morphologies of the electrodeposited catalysts are observed by a scanning electron microscope. The electrochemical activity in methanol oxidation is examined by the cyclic voltammetry using a mixed aqueous solution of methanol as an electrolyte component. As the cycle number increases, both the current density and the amount of the electrodeposited metallic particles on the CF web are increased. The Pt-Ru-Ni/CF catalyst prepared in the potential range of -0.6 to 0.2 V and from the 1:2:2 mixed solution of H₂PtCl₆, RuCl₃·3H₂O, and Ni(NO₃)₂·6H₂O, respectively, shows the higher current density, corresponding to the higher catalytic activity.