Abstract: High-specific-surface-area activated carbon (HSAAC) was prepared from bamboo char by activation with KOH. The specific surface area and pore structure of activated carbon were characterized by nitrogen adsorption isotherm at 77 K. The specific surface area, mesopore volume and total pore volume increased with the ratio of KOH to carbon. The iodine and methylene blue adsorption values of the HSAAC increased with the increased ratio of KOH to carbon at first and then decreased, at the ratio value of 4, the values reached the maximum, or 2 168 and 569 mg/g respectively. Moreover the performance in charge and discharge of electric double-layer capacitor EDLC using HSAAC as electrodes and relation between specific capacitance and different factors were discussed. The results show that HSAAC sample from the ratio of KOH to carbon of 4 presented a high specific surface area (2610 m2/g) and total pore volume (1.24 cm3/g) and its specific capacitance reached 206 F/g in 30% H2SO4 aqueous electrolytes.