Abstract: In this paper, three-dimensional hierarchical porous carbons (HPCs) were prepared using coal tar pitch as raw material and α-Fe₂O₃ as template combined with KOH activation. The as-prepared HPC-3 showed large specific surface area (2003 m²/g), which was due to the synergistic effect of the occupation of α-Fe₂O₃ (certain mesopores and macropores) and KOH activation (abundant micropores). And the assembled electric double layer capacitor by HPC-3 exhibited the largest specific capacitance (295 F/g) and superior cycling stability (specific capacitance retention of 97.8% after 10000 cycles) in 6 mol/L KOH electrolyte. Meanwhile, the high working voltage (3.6 V) and energy density (60.0 (W·h)/kg) were obtained when it was applied to EMIMBF₄ electrolyte.