Nitrogen-doped hierarchical porous carbon has been prepared by carbonization and hydrofluoric acid treatment of the electrospun carbon nanofibers from the polymer solutions containing thermoplastic polyurethane and also polyacrylonitrile which acted as the precursor. Controlling the nitrogen content by varying thermoplastic polyurethane mass fraction in the spinning solutions was to realize different concentration doped. Assembling a symmetrical supercapacitor by using 6 mol/L KOH as electrolyte and relevant detections were carried out. N-2 adsorption/desorption measurement indicates the sample containing 10 wt% thermoplastic polyurethane possesses the large specific surface area of 1,126 m(2) g(-1) and holds volume value of 0.424 cm(3) g(-1). The electrochemical performances were investigated by cyclic voltammetry, electrochemical impedance, and charge-discharge cycling techniques in a two-electrode system. And the sample containing 10 wt% thermoplastic polyurethane exhibits specific capacitance of 207, 203, and 198 F g(-1) at the current density of 0.2, 0.5, and 1.0 A g(-1), respectively. Moreover, the capacity faded lower than 1 % after 8,000 cycles of charging and discharging, indicating its excellent electrochemical stability.