Nanosized TiO2/SiO2 particles were prepared by hydrolysis of TTIP (titanium isopropoxide) and TEOT (tetraethylorthosilicate) in sodium bis (2-ethylhexyl)sulfosuccinate (AOT) reverse micelles. The mole fraction of TEOS was 0.1. The physical properties, such as surface area, thermal stability, crystallite size and crystallinity according to W0 ratio have been investigated by TEM, XRD, BET, FT-IR, TGA and DTA. In addition, the photocatalytic degradation of p-nitrophenol has been studied by using batch reactor in order to compare the photocatalytic activity of prepared nanosized TiO2/SiO2 particles. It is shown that the XRD pattern of the particle heat treated at 105 ℃ and 300 ℃ indicates amorphous and the major phase of all the prepared particles were anatase structure. No significant rutile phase was observed although the calcination temperature at 800 ℃ and no peaks SiO2 crystal were also observed for TiO2/SiO2 (90/10). The presence of amorphous SiO2 in TiO2/SiO2 particle enhanced the thermal stability of TiO2 particle resulting in the suppression of the phase transformation from anatase to rutile phase. The crystallite size of prepared particles decreased with decreasing W0 ratio. The surface area increased with decreasing W0 ratio. In addition, TiO2/SiO2 (90/10) particles shows higher photoactivity than that of pure TiO2 particles.