The electrochemical performance of polyaniline (PANI) and polypyrrole (PPy) coaxial nanofibers as supercapacitor electrode materials was evaluated by electrochemical impedance spectroscopy. The influence of the shell layer thickness on the charge transport and transfer process for the coaxial nanofibers in aqueous Na2SO4 solutions was studied. It is found that the existence of strong interaction between PANI and PPy, good orientation of conducting polymer chains, and large surface area to volume ratios in coaxial nanofibers are a benefit to the sufficiently diffusion of the charges, which demonstrates that the resulting nanofibers have potential application as electrode materials for supercapacitor.