Abstract: TiO2 films with different crystalline particle size，pore size and light transmittance were prepared by sol-gel method through varying the aging temperature and period. TG-DSC and FTIR analysis for the dried gel film indicated that acetylacetone has been bounded to the polymer chain，and the amount of organic components in the gel decreases as the aging temperature or period increase. XRD results revealed that the crystalline size decreases with the aging period increase. TEM observation suggested that the prepared film shows a honeycomb microstructure，and both the pore size and the wall thickness decrease with the aging period increase. The pores formed mainly due to the oxidation and degradation of organic components，and the pore size depended on the composition of organic components. The films prepared with sols aged at 80 ℃ for 24 h or at 150 ℃ for 2 h performed an excellent light transmittance of 96% and 90% respectively.