Abstract: The electrochemical storage of energy was considered in a special kind of active carbon materials used as capacitor electrodes. The porous carbon material prepared by KOH and vapor re-etching exhibits perfect physical structure and properties. Its good electrochemical performances were confirmed by the experiment of charge/discharge and the specific capacitance of active carbon was 173.2 F/g. Under the large discharge current condition, the specific capacitance of EDLC decayed only 12 F/g. A evaluation of capacitor performance by voltammetry characteristics was also discussed. A hybrid power source consisting of Nickel-hydrogen and double layer capacitor was demonstrated to power successfully a simulated power load encountered in communication equipment. The new technique of getting high working voltage for capacitor was discussed in detail. The working voltage over 10 V and the resistance less than 250 Ωm was obtained.