Abstract: The solid material of coupled semiconductor SnO2-TiO2 was prepared by sol-gel method. The Photocatalyst SnO2-TiO2 supported metallic Cu was prepared by an isovolumic impregnation method. The surface structure, particle size, photo absorption performance and photocatalysis performance of the materials were characterized by X-ray diffraction， Laser Raman spectroscopy, Temperature programmed reduction and Infrared spectroscopy, Transmission electron microscopy, Ultraviolet-visible diffuse reflectance spectroscopy and Micro-photoreactor. The experiment results show that 10%SnO2 disperses on the surface of TiO2 support with one monolayer of non-crystalline phase, and the average particle size of 1%Cu/10%SnO2-TiO2 is about 22 nm. Blue shifting of photo absorption edges is observed clearly after addition of SnO2 on the surface of TiO2. The crystalline phase SnO2 forms and photo absorption performance decreases when supporting amount of SnO2 is more than the monolayer phase(>10%). The formation of Ti-O-Sn bond in the solid systems promotes transfer of generating charge carriers between TiO2 and SnO2. Loaded metallic Cu increases the photo absorption capacity of the photocatalyst and enlarges photo absorption range to visible light. Photo absorption performance and quantum efficiency of the photocatalysts have a corresponding relationship with various Sn content. Both photo absorption performance and quantum efficiency of the reaction on 1%Cu/10%SnO2-TiO2 are the best among the others, and the quantum efficiency reaches 13.9%.