A series of composite photo-catalysts were synthesized by sol-gel and impregnation process using silver nitrate, titanium tetrachloride and activated carbon as raw materials. The physical and chemical properties of the composite photo-catalyst, such as morphology、phase composition、specific surface area and optical absorption properties, were characterized by using TEM、XRD、BET and UV-Vis techniques. Taking methyl orange degradation as a model reaction, the photo-catalytic activity of the photo-catalysts were investigated. The results indicate: Ag/TiO2/AC>Ag/TiO2>TiO2. Among them the Ag/TiO2/AC with adsorption, photo-catalytic double-effect function have the highest photo-catalytic activity and its absorption of light extended to visible light region because of its larger specific surface area and modification by loading of silver. Its photo-catalytic activity didn’t basically decrease when it was repeatedly used for 5 times.