Hierarchical porous activated carbon (AC) was obtained from corn stalk pith with a hierarchical macroporous nature, which is composed of cells of soft and spongy texture. The high specific surface area (2495 m(2) g(-1)) of the activated carbon (AC) was produced by the activation of corn stalk core (CSC) using potassium hydroxide at 700 degrees C. SEM, TEM and XRD were used to test the microstructure and crystallographic orientation of the carbon samples. The cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy were measured based on CSC-700. This sample had relatively low inner resistance of 1.0 Omega. The specific capacitance was 323 F g(-1) in 6 mol L-1 KOH electrolyte at a current density of 0.1 A g(-1), and it still maintained very good cyclic stability with capacitance retention ratio of 97.9% (from 265.0 to 262.4 F g(-1)) at current density of 1.0A g(-1) for 1000 cycles. (C) 2016 Published by Elsevier Ltd.