Nanoporous carbons were prepared from rice husk (RH) according to a three-step procedure that includes pre-carbonization, silica removal and chemical activation. The surface area and pore structure of the nanoporous carbons are characterized intensively using N2 adsorption technique. The as-prepared carbons have specific surface area of up to 3283 m2/g, and total pore volume of up to 1.8 cm3/g. The effect of activating agent dosage on the pore structure of carbons was investigated and elucidated clearly. As evidenced by electrochemical measurements, the as-prepared carbons have good capacitive performances and their specific capacitances are much higher than ordered mesoporous carbon, thus highlighting the success of preparing high performance electrode material for EDLC from a biomass waste, rice husk.