In this work, a three-dimensional hierarchical carbon framework/Co3O4 hybrid composite was fabricated. The three-dimensional hierarchical carbon framework was constructed by thermal vapor deposition on the silica nanosphere templates and etching these templates. The resulting carbon framework was activated using phosphoric acid to control its surface area and porosity. The degree of activation of the carbon framework was optimized by measuring the specific capacitance. The carbon framework electrode activated with 3 M phosphoric acid (HCCA(3)) exhibited the highest specific capacitance (134 F g(-1) at 10 mV s(-1)). Subsequently, Co3O4 was formed on the carbon framework via the hydrothermal method. The resulting product HCCA(3)/Co3O4 showed a dramatic enhancement in the specific capacitance (456 F g(-1) at 1 A g(-1)) compared with the pristine Co3O4 and HCCA(3) electrodes. The proposed HCCA(3)/Co3O4 composite can be used for the fabrication of high-performance electrodes.