− Nanosized TiO 2 particles were prepared from titanium (IV) sulfate solution using base solutions at low reaction temperature (95 o C) and atmospheric pressure by hydrothermal precipitation method without calcination. The effects of preparation conditions, such as kind of base solutions (NaOH, NH 4 OH, Monoethanolamine, Diethanolamine, Triethanolamine) and surfactants (CTAB, Span 20, SDBS), concentration of surfactants, temperature and pH, on the physical properties of TiO 2 particles have been investigated by XRD, SEM and Zeta-potential meter. Absorption area was also investigated by DRS in order to confirm the photocatalytic activity of the nanosized TiO 2 particles. It was turned out that, among base solutions, NaOH provides the smallest TiO 2 particles with excellent crystallinity. And cationic surfactant (CTAB) prepared smaller TiO 2 particles than any other surfactants. When CTAB is added in the concentration ratio of Ti(SO 4 ) 2 :CTAB=10:1, TiO 2 particles with particle diameter of 5.8 nm were prepared. This is approximately 1/10 of that prepared without CTAB.