Inorganic perovskite barium titanate nanowires (BTNWs) and their nanocomposites comprised of different weight percentages (1, 2, and 3 wt%) of graphene nanoplatelets (GNP) are synthesized via a hydrothermal method and used as photoanode materials of dye-sensitized solar cells (DSSCs). Morphological analysis of the BTNWs and BTNWs + GNP composites has indicated that the one-dimensional BTNWs and two-dimensional GNP are formed as uniformly distributed, well-connected mesoporous microstructures. UV–visible absorption and Raman studies of the BTNWs + GNP composites have revealed a narrowing bandgap, improved visible light absorption with increasing GNP content, and a superior light-scattering effect of BTNWs. Besides, four different DSSC bilayer photoanodes comprising titanium dioxide nanoparticles (TNP) underlayer and an upper layer with BTNWs + (0, 1, 2, and 3 wt%) GNP composites are fabricated to elucidate the TNP + BTNWs and BTNWs + GNP composite sublayer(s) influences on the photovoltaic performance. The TNP + BTNWs + 2 wt% GNP composite bilayer photoanode has demonstrated a higher power conversion efficiency of 9.92 % as compared to that of the other TNP + BTNWs + GNP composite bilayer photoanodes in DSSCs, due to the higher charge recombination resistance, faster charge transport, superior charge collection ability and carrier lifetime of its sublayers.