The properties of TiO2 film prepared by titanium tetrachloride were investigated with respect to annealing temperatures in terms of phase change, crystallite size, and band gap energy. The TiO2 film dried at room temperature exhibited an amorphous phase, while films calcined above 281 and at 990 o C displayed anatase TiO2 and a mixture of anatase and rutile, respectively. The TiO2 film was transformed to an anatase phase through three stages during the annealing processes: (1) removal of water, (2) decomposition of a peroxo group, and (3) amorphous-anatase phase transformation. It was also found that the bandgap energy of TiO2 film was changed with increasing annealing temperature. This is attributed to the quantum size effect in the range of 475-675 o C and to the formation of rutile phase having lower band gap energy than anatase in the range of 675-990 o C.