Co3O4 microspheres were synthesized by hydrothermal-precipitation method using NH3•H2O, H2O2, n-butanol and polyethylene glycol as precipitator, oxidant, assistant solvent and dispersant respectively. The products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical properties of the Co3O4 electrode were performed by cyclic voltammetry (CV) and galvanostaitc charge/discharge methods. The results exhibited that the Co3O4 single electrode had excellent stability, cyclic performance and high specific capacitance in KOH electrolyte. The specific capacitance as a single electrode was up to 653.74 F/g in the 6mol/L KOH solution with 0-0.4V potential at 2mA/cm2 current density. The effects of electrolyte concentrations and current densities on its capacitive performance were investigated. The Co3O4 prepared material is potential candidate for the preparation of power source devices.