Abstract: Supercapacitors,known as Double-Layer Capacitors,have higher energy density than conventional capacitors and higher power density than batteries.Specific capacitance of 52 F·g^-1 in a single cell was achieved In this work,by using activated carbon as electrode material.Furthermore,a 3 V capacitor with the capacit ance of 1000 F was prepared in series and parallel connection.Its equivalent series resista nce(ESR)was measured to be 56 mΩ,the equivalent leakage resistance and leakage current were 170 Ω and 15 mA respectively.The performa nces of charge/discharge cycle,load and leakage were also studied.Some discussion was made in the galvanstatic charge/discharge and leak process.