This study provided a simple method to form NiO nanostructures onto the carbon nanowalls (CNWs) surface to enhance the performance of electric double layer capacitor (EDLC) characteristics. The CNWs were synthesized on carbon cloth by rf magnetron sputtering without any catalyst. Ni film was then deposited on the synthesized CNWs by e-beam evaporator. Subsequently, the vacuum annealing process and oxygen plasma treatment were used to form the NiO nanostructures. The crystallize structures of NiO nanostructures and CNWs were examined by Raman scattering spectroscopy. To realize the electrochemical properties of NiO/CNWs/carbon cloth composite, cyclic voltammetry (CV) and galvanostatic charge-discharge tests were investigated. Due to the relatively larger surface area of CNWs and the quickly reversible redox reaction and pseudo-capacitive properties of NiO nanostructures, the measured results demonstrated that the NiO/CNWs/carbon cloth is a suitable electrode material for EDLC applications. (C) 2012 Elsevier B.V. All rights reserved.