Ni-decorated carbon nanotube (CNT) film of a networklike architecture has been formed on a stainless steel substrate by electrophoretic deposition (EPD) in CNT suspension containing nickel nitrate. Adsorption of nickel ions on the CNTs increases the measured zeta potential and consequently favors the dispersion and EPD of CNTs. Nickel ions are reduced on the CNT surface to form Ni-decorated CNT film in the EPD process. The deposited nickel layer plays an important role in improving the adhesion, wettability, and electrochemical reaction of the film. Therefore, the Ni-decorated CNT film exhibits an excellent capacitive behavior compared with the bare CNT film.