Highly flexible metal-free fiber fibrous electrodes are prepared using commercial carbon fiber (CF) and poly(3,4-ethylene dioxythiophene)-polystyrene sulfonate (PEDOT:PSS) aqueous solution. Multiple highly ordered CF monofilaments acted as the conductive cores, while the PEDOT:PSS film acted as the catalytic shell in the composite fiber fibrous electrode. Cyclic voltammetry and electrochemical impedance spectroscopy were carried out to systematically investigate the electrochemical performance, and the results indicate that the composite fibrousfiber electrode is highly efficient in catalyzing I3－/I－. The PEDOT: PSS conductive film also showed excellent compatibility with CF and resistance to solvent. The low-cost composite electrodes were used as counter electrodes to fabricate fiber-shaped dye-sensitized solar cells, and the highest conversion efficiency of 5.5% was achieved, which is comparable to the performance of a platinized CF counter electrode-based device.