Nanosized titanium oxide (TiO2) powders of various amorphous-anatase-rutile phases were prepared by hydrolysis using an economic inorganic compound TiCl4 as precursor. The powders were characterized by transmission electron mocroscopy (TEM), X-ray diffraction (XRD) and Brunnauer-Emmett-Teller (BET) techniques. Thermogravimetry analysis (TGA), differential thermal analysis (DTA) and DSC were performed on the prepared powders. The,effects of small amount of sulphate ions and hydrolysis temperature on the morphology and crystallization were analyzed. The mass fraction of nanosized amorphous TiO2 was determined by DSC first time.