Abstract: NiO was obtained by thermal decomposition of Ni(OH)₂ precursor that synthesized via hydrothermal process using SDS as surfactant.The structure and morphology of the precursors and products were characterized by TGA, XRD and SEM.The results showed that the morphology of NiO was nanostructured flower-like at 300℃.The capacitance performance of NiO single electrode was researched by cyclic voltammetry and galvanostaitc charge/discharge methods.The results indicated that the NiO electrode had typical pseudocapacitive behavior.The NiO single electrode, which was synthesized by hydrothermal-decomposition, had good electrochemical property and the specific capacitance was up to 826.4 F·g^-1 in 6M KOH electrolyte concentration with 0 to 0.4V potential(vs.SCE).