Abstract: The high surface area activated carbon was produced firstly by a simple two-step process of carbonization and KOH activation using forestry and agricultural residues sword bean shells as precursor. Furthermore, the N and B co-doped hierarchical porous carbon was prepared by hydrothermal post-treatment process using ammonium pentaborate tetrahydrate(NH₄B₅O₈·4H₂O) as nitrogen and boron source. The scanning electron microscopy, transmission electron microscopy, nitrogen adsorption/desorption isotherm and inductive coupled plasma emission spectrometer were used to investigate the morphological, structural and chemical properties. Meanwhile, the electrochemical performance was tested by a three-electrode system. The results showed that the maximum specific surface area, total pore volume, and micropore volume of the doped activated carbons could reach 2 859 m²/g, 1.34 cm³/g, and 0.99 cm³/g, respectively. The boron and nitrogen contents were 3.27% and 2.60%. The B and N co-doped activated carbon materials possessed excellent rate performance. Due to the synergistic effect of heteroatoms doping and also appropriate texture properties, the maximum specific capacitances were 369 and 240 F/g at the current density of 1 and 20 A/g, respectively.