Titanium oxide ST01, ST31, TiO2 catalysts modified by V5+, N2+ and supported on MCM41 and SiO2 have been used for photooxidation of p-xylene in gas phase. Physicochemical properties of catalysts were determined by the methods of BET Adsorption, Xray Diffraction (XRD), UV-Vis spectroscopy, and atom adsorption spectroscopy (AAS) methods. The photocatalytic activity of catalysts were determined after thermal treatment as well as UV lighting. The common observation is that the higher temperature of treatment the lower conversion of p-xylene obtained. Additives change the photoactivity, p-xylene adsorption, carbon deposit amount and stability of catalysts. TiO2 - V- doping have been shown to be the best catalyst for p-xylene photooxidation in gas phase.