Abstract: TiO2/ AC (activated carbon) composite photocatalysts were prepared by acid catalyzed hydrolysis method followed by calcinations in N2 atmosphere. Photocatalytic activity of TiO2/wAC (w: the mass fraction of AC, %) was investigated through the photocatalytic degradation of phenol, methyl orange, and Cr6+ in the present of TiO2/wAC. The separability of TiO2/AC was determined by gravity-sedimentation. XRD, DRS, FTIR, SEM, and N2 adsorption isotherm were used to characterize the crystal structure, spectra characteristics, and surface properties of the obtained catalysts. The results showed that TiO2/wAC catalysts with optimal AC content 5%(w) exhibited more higher activity than P-25 and TiO2, as well as od decantability, less activity lost after several runs and less sensitive to pH change.Result of DRS revealed no electronic change when AC was added. Better TiO2 distribution and less agglomeration can be achieved when optimal AC content adopted. Result of FTIR suggests that a conjugation effect was presented between the AC bulk and Ti—O bond. Suitable pollutant concentration environment and less agglomeration provided by AC was the main cause for the high activity of TiO2/5AC. The performance of the prepared TiO2/5AC catalyst revealed great practical potential in waste water treatment.