Sol-gel method is a way to obtains broad scale processing of nanostructure materials. This study utilized five different sol-gels with adjust various pH values and post-sintering conditions to derive the formation of nano-titania particles. It is successfully to control particle size and phase under mulit parameters. Amorphous titania was obtained at low post-sintering temperatures about 300ºC, Mixtures of anatase and rutile phase titania were observed at intermediate temperatures of 350 ~ 600ºC, Escalate temperature until 800ºC, There are 100% rutile titania was obtained. The phase formations of transfigurations have been proved via multi parameters by XRD. Particle morphology, size and agglomeration are observed by TEM. Within different pH values, the sizes of titania particles varied from 20 to 100 nm. Depending process conditions can be effect nano-titania size directly. Achieve to increase contact area or porous structure. The rapid expansion supercritical solution (RESS) method has been applied to deposit dense (30 nm thick) and porous nano-crystalline TiO₂ (5–20 μm thick) layers incorporated in dye-sensitized solar cells (DSSCs). The DSSCs fabricated with the TiO₂ layers deposited by RESS method on ITO glass showed a power conversion efficiency of 4.3% under an illumination of 10 mW/cm².