In this study, we demonstrate a new kind of Pt-free counter electrode for dye-sensitized solar cells (DSSCs). Polyaniline-graphene quantum dots (PANI-GQDs) nanocomposite, with the advantages of low cost and simple preparation, was prepared by in situ electrochemical polymerization of an aniline monomer in the presence of GQD and it shows good catalytic activity in promoting tri-iodide reduction. The fluorine-doped tin oxide (FTO) coated glass was immersed into the solution of the aniline and GQD during the polymerization of PANI. The PANI-GQD nanocomposite was in situ deposited onto the surface of FTO glass. Formation of PANI and PANI-GQD films was confirmed by FE-SEM, TEM, XRD, and FT-IR analysis. The DSSC composed of the PANI-GQD nanocomposite electrode exhibits an energy conversion efficiency of 1.6 %. The presence of the synergistic effect of PANI and GQD led to the higher electrochemical catalytic activity of PANI-GQD nanocomposite than that of pristine PANI. As a result, better photovoltaic performance was observed for DSSCs based on the PANI-GQD electrode as compared to that of the DSSC sample based on the PANI electrode.