Abstract: The nanocrystalline nickel oxide was prepared by a citrate-gel method.The results showed that the NiOx prepared in the optimum condition (CA:Ni2+ mole ratio 1.3:1.0,annealing at 400℃ for 1h).The electrochemical capacitive behaviors of the NiOx electrodes were characterized by Cyclic Voltammetry (CV),chronopotentiometry (CP) and A.C.impedance in 1 mol/L KOH aqueous solution.The electrochemical measurements indicated that the prepared samples exhibited high specific capacitance of 78.74 F/g,and excellent cyclability.