Porous carbon nanofibers (CNFs) enriched with the graphitic structure were synthesized by thermal decomposition from a mixture containing polyethylene glycol and nickel chloride (catalyst). The textural and electrochemical properties of porous CNFs were systematically compared with those of commercially available multi-walled carbon nanotubes (MWCNTs). The high ratio of mesopores and large amount of open edges of porous CNFs with a higher specific surface area, very different from that of MWCNTs, are favorable for the penetration of electrolytes meanwhile the graphene layers of porous CNFs serve as a good electronic conductive medium of electrons. The electrochemical properties of porous CNFs and MWCNTs were characterized for the application of supercapacitors using cyclic voltammetry, galvanostatic charge–discharge method, and electrochemical impedance spectroscopic analyses. The porous CNFs show better capacitive performances (C S =98.4Fg−1 at 25mVs−1 and an onset frequency of behaving as a capacitor at 1.31kHz) than that of MWCNTs (C S =17.8Fg−1 and an onset frequency at 1.01kHz). This work demonstrates the promising capacitive properties of porous CNFs for the application of electrochemical supercapacitors.