TiO2 powders were prepared from titanium (IV) sulfate (Ti(SO4)2) solution using ammonia solution at low reaction temperature (80~100 ℃) and atmospheric pressure by hydrothermal precipitation method without calcination. The effect of reaction conditions, such as reaction temperature, initial concentration of titanium (IV) sulfate (Ti(SO4)2) solution, pH of mixture solution and the physical properties of the prepared TiO2, such as crystallite structure, crystallite size were investigated. The photocatalytic activity of prepared TiO2 was tested by the photolysis of brilliant blue FCF (BB-FCF) under the UV and the analysis of UV-VIS diffuse reflectance spectroscopy (DRS). The physical properties of prepared TiO2 were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence spectrometer (PL), particle size distribution measurements. The crystallite size and crystallinity of prepared TiO2 increased with increasing titanium (IV) sulfate (Ti(SO4)2) concentration, but photocatalytic activity decreased. The crystallite size decreased with increasing pH of mixture solution, but photocatalytic activity increased. The crystallinity and photocatalytic activity increased with increasing reaction temperature. The results showed that anatase type TiO2 could be prepared by hydrothermal precipitation method using titanium (IV) sulfate (Ti(SO4)2) solution and ammonia solution at low reaction temperature and atmospheric pressure without calcination.