Abstract: Activated carbon for supercapacitor was prepared from coconut shell carbide by KOH activation. The effects of the ratio of KOH/carbon, activation temperature and activation time on the pore structures and specific capacitance of activated carbon were investigated. The results showed that the high quality activated carbon as electrode material could be prepared under the conditions of the mass ratio of KOH/carbon 4:1, activation temperature 800℃ and activation time 60 min. Under these conditions, its specific surface area of the sample was 2 891 m2/g, total pore volume was 1.488 cm3/g, the mesopore ratio was 73.6 % and specific capacitance was 235 F/g.