Photoelectrodes using different nanoparticle size and film thickness of TiO2 were prepared by screen-printing and post annealing method with the objective of optimizing the photovoltaic performance of dye-sensitized solar cells (DSSCs). The effect of nanoparticle size and film thickness of the TiO2 on the performance of DSSCs was investigated. Based on the effect investigation, composite nanoparticulate TiO2 film electrodes were designed and fabricated to improve the photovoltaic performance of the DSSCs. The enhanced conversion efficiency was achieved in the DSSCs by introducing light scattering layer and additional dye adsorption nanoparticle layer to form composite TiO2 films, and by optimizing the nanoparticle size and film thickness. The improvement mechanism was also discussed.