Activated carbons for electrochemical capacitor electrodes are prepared from soyabean using chemical activation with KOH.The pore size is easily controllable by changing the mass ratio between KOH and carbonized product.The as-prepared materials possess a large specific surface area,unique structure,well-developed hierarchical porosity and plentiful heteroatoms (mainly O and N).Thus resulted in its high specific capacitance,good rate capacity and cycling stability.Moreover,attributing to worldwide availability,renewable nature and low-cost,activated carbon prepared from soyabean has a good potential in energy conversion and storage devices.