||In this study, porous carbon nanofibers (PCF) is prepared for supercapacitor electrode applications by using nanosize polyacrylonitrile (PAN) fibers as a precursor, following treatments at various activation times. The surface and structural characteristics PCF were observed by scanning electron microscopy and X-ray diffraction, respectively. N2 adsorption isotherm characteristics at 77K were confirmed by Brunauer-Emmett-Teller (BET) and Dubinin-Radushkevich (DR) equations. The pore size distributions of the samples were calculated by employing the regularization method according to density functional theory (DFT). As experimental results, many holes or demolished structures were found on the fiber surfaces after the KOH activation as confirmed by the SEM analysis. Specific surface areas and pore volumes of the PCF prepared were enhanced with increasing activation time. PCF were applied as an electrode for electrical double layer capacitors in terms of the activation conditions.