-Globally, the use of titanium dioxide (TiO 2 ) for photocatalytic activities has a tremendous attention because of the numerous advantages which can be obtain from photocatalysts. The usage of TiO 2 was verified to be nontoxic, biologically inert, physically and chemically stable against corrosion. The TiO 2 photocatalyst was prepared via a simple precipitation method using titanium tetrachloride (TiCL) in the presence of ammonium sulfate was used to obtain samples of mesoporous titanium dioxide with anatase structure. In the work discussed in this paper, titanium dioxide (TiO 2 ) nanoparticles were synthesized by wet precipitation method under different conditions. Prepared TiO 2 powders were characterized by XRD, FESEM and UV Vis-DRS. Different conditions, for example reflux time ( 2 and 4 hours) and calcination temperature (3 50°C), were changed to achieve to best nanocrystallite material. It was found that variation of all these conditions could strongly affect crystallinity, morphology, and crystallite size. The crystallite sizes of nanoparticles, calculated by using the Scherrer equation, were from approximately 11 to 15 nm. © Published under licence by IOP Publishing Ltd.