Novel carbon nanotubes (CNTs)–polyethylene oxide (PEO) composite electrolyte for dye-sensitized solar cell (DSSC) was prepared and characterized for the first time. The strong bonding and interaction between CNTs and PEO in CNTs–PEO composites was observed by the characterization of X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and Raman spectra. The introduction of CNTs into PEO matrix significantly improved the electrolyte properties of DSSC such as roughness, amorphicity and ionic conductivity. The solid-state DSSC fabricated with the optimum composite electrolyte (added 1% CNTs in PEO matrix, 1%CNT–PEO) achieved maximum conversion efficiency of 3.5%, an open circuit voltage (V OC ) of 0.589V, short circuit current density (J SC ) of 10.64mA/cm2 and fill factor (FF) of 56%. The highest IPCE in the DSSC fabricated with 1%CNT–PEO electrolyte is ascribed to the improved ionic conductivity of composite electrolytes and enhanced interfacial contact between electrode and electrolyte.