A flexible Poly (3, 4-ethylenedioxythiophene) (PEDOT) electrode on indium-doped tin oxide coated polyethylene naphthalate (ITO-PEN) substrate is prepared by electrochemical methods for dye-sensitized solar cells (DSSCs) as counter electrode. The impact of deposition time on the catalytic activities of the flexible PEDOT electrode towards the iodide redox couple has been investigated by cyclic voltammetry, electrochemical impedance spectroscopy (EIS) and Tafel polarization curve measurements. After optimization, the DSSCs using PEDOT counter electrode deposited 80 s shows power conversion efficiency (PCE) of 7.18%, close to than the Pt counter electrode based counterpart (7.56%). To further improve the catalytic activity of PEDOT, Pt/PDEOT composite catalyst is synthesized. And the DSSCs with the Pt/PDEOT composite CE generates a high PCE of 7.90%.