Abstract: Colorless transparent TiO₂ sol and nano TiO₂ powder were prepared by sol-gel process with butyl titanate(TBOT) as precursor,anhydrous ethanol as solvent,water as reactant,hydrochloric acid as catalyst.The condition of preparing colorless transparent TiO₂ sol was optimized by orthogonal test and range analysis.The optical property of the TiO₂ was investigated by means of UV-Vis spectra analyzing,the molecular structure was characterized by means of FT-IR spectrum,thermal property was detected via TGA and DSC and the crystal form and its nano-size were analyzed by meas of XRD.The results show that the colorless transparent TiO₂ sol has very weak absorption in the visable light region,and strong absorption in the ultraviolet light region,so is suitable for uvio-resistant agent and the TiO₂ powder is thermal stable,could resist high temperature over 300℃,So is suitable for heat-resisting filler.The as-prepared TiO₂ samples possess anatase phase crystal structure with granule size around 35nm.