Highly porous carbons were prepared from sunflower seed shell (SSS) by chemical activation and used as electrode material for electrochemical double layer capacitor (EDLC). The surface area and pore structure of the porous carbons are characterized intensively using N2 adsorption technique. The results show that the pore-structure of the carbons is closely related to activation temperature. Electrochemical measurements show that the carbons have excellent capacitive behavior and high capacitance retention ratio at high drain current, which is due to that there are both abundant macroscopic pores and micropore surface in the texture of the carbons. More importantly, the capacitive performances of these carbons are much better than ordered mesoporous carbons, thus highlighting the success of preparing high performance electrode material for EDLC from SSS.