Conductive carbon nanoparticles were introduced into PEO/P(VDF-HFP)/SiO2 nanocomposite polymer electrolyte for dye sensitized solar cells (DSSCs). The conductive rnechanism is changed by adding different amount carbon nanoparticles: 2.5, 5, 7.5, and 15 wt.%. AC impedance measurements and DC voltage-current measurements were Carried out to analyze the conductive mechanism of the composite polymer electrolyte (CPE in short). DSC thermograms also indicated the configuration change of the different carbon nanoparticles content modified CPE. Small amount of carbon nanoparticles modification improved the ionic conductivity and the solar to electric energy conversion efficiency of DSSC with 5 wt.% carbon nanoparticles modified CPE is improved to 4.27% compared with the original DSSC performance of 3.87%. Too much carbon nanoparticles content in CPE is unfavorable for the ionic conductivity and the electronic conductive path is formed in it. The efficiency of 15 wt.% carbon nanoparticles modified CPE type DSSC is decreased to 3.61%. (c) 2007 Elsevier B.V. All rights reserved.