The photocatalytic activity of mesoporous TiO2 modified by the carbon nanotubes (CNTs) and Ag is reported. The mesoporous TiO₂ was synthesized by sol-gel method and mechanically mixed with functionalized multi-wall carbon nanotubes which was decorated by different amount of Ag. Mesoporous TiO₂ and the nanocomposite were characterized by XRD, SEM, TEM, BET surface area analysis, FTIR, AAS, UV-Visible, DRS-UV and UV-Vis absorption spectroscopy. The photoactivity of nanocomposite containing mesoporous TiO₂, MWCNT and Ag were evaluated by the degradation of methyl orange (MO) in aqueous solution under UV irradiation. Results showed that the CNT which was decorated with the 15.5% of Ag could facilitate the phocatalytic activity of mesoporous TiO₂.