Silver-modified TiO2/SnO2 thin films (Ag-TiO2/SnO2 thin films) were prepared by the photodeposition method. The effects of preparation conditions on the photocatalytic activity of Ag-TiO2/SnO2 thin films were discussed. The surface morphology, chemical composition and structure of the films were characterized by SEM and XRD, and its photocatalytic properties were evaluated with Rhodamine B as model compound. The results show that the optimum content of Ag on the film surface was 0.51at% and the diameter of Ag particles was about 30~90 nm. The photocatalytic degradation rate of Ag-TiO2/SnO2 film is 1.92 times and 2.54 times higher than the TiO2/SnO2 film and the TiO2/ITO film, respectively, mainly duo to the change in the reaction mechanism. The heterojunction of Ag-TiO2 in Ag-TiO2/SnO2 film efficiently promoted the separation of charges and accelerated the reaction of excited electrons and oxygen relatively to TiO2/SnO2 film in photocatalytic degradation for Rhodamine B