Self-assembled TiO2-based air-water interfacial particles with nano structure were soaked into silver nitrate (AgNO3) aqueous solution and Ag-TiO2 composite nanoparticles were obtained by the heat-treatment at 400 oC. The composite nanoparticles were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and ultraviolet visible spectrum (UV-Vis). The results show that the Ag-TiO2 particles at 400 oC could significantly enhance the photocatalytic activity of the TiO2 particles. Methyl orange was used as the degradable agent in photocatalytic experiment. The results indicate that methyl orange could be degraded 96.25% by Ag-TiO2 nanoparticles under the optimal conditions. It is concluded that the Ag-TiO2 composite nanoparticles posses good photocatalysis activity.