The improvement of the strength and structure of a porous titanium dioxide (TiO2) thin film on a plastic film substrate as an electrode for dye-sensitized solar cells (DSCs) were investigated. Although a film type DSC is lightweight and flexible, it shows a poor binding to a substrate compared with a glass type DSC. By the use of the ordinary TiO2 slurry including a volatile solvent the thin film forms a lot of cracks during the drying process because of a rapid removal rate of the solvent and a strong interaction between TiO2 particles. In this study, we prepared well dispersed TiO2 slurry by using a planetary ball mill and it was condensed by centrifugal sedimentation. High concentration slurry is appropriate for the coating and drying because it has a small amount of solvent and good stability of liquid film after the coating. Further, the crack produced on the surface of the thin film could be reduced in a slow drying process by the control of the pressure and atmosphere. The TiO2 thin film, which was produced by the improved methods of slurry preparation and drying condition, showed good cohesiveness to a plastic film substrate.