Abstract: Taking TiOCl₂ solution prepared by hydration of TiCl₄ as raw material,crystalline TiO₂powder was prepared by pyrohydrolysis of self-generating seed crystal under a pressure of 1 atm. With Ti⁴⁺ concentration in the initial TiOCl₂ solution of 0.5 mol/L,after reaction at 106℃ for 120 min,the product obtained was proved to be a mixture of rutile,anatase and brookite powder by X-ray diffraction analysis. And pure rutile TiO₂ powder could be prepared after calcination. The influence of the concentration of Ti⁴⁺ and reaction temperature and time on size distribution of the products was investigated. It can be concluded that with Ti⁴⁺ concentration of 0.5 mol/L and reaction time of 120 min,TiO₂ power with minimum particle size can be obtained,and as the hydrolysis temperature reduces,the TiO₂ particle size becomes smaller.