In this work, silver-doped titanium dioxide (Ag-doped TiO2) nanostructures synthesized by a dc reactive magnetron co-sputtering technique at different gas mixing ratios (Ar:O2). The structural and spectroscopic characteristics of the prepared samples were introduced by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy and UV–visible spectroscopy. The XRD results reveal that all samples have anatase phase of tetragonal system. The functional groups of these samples were identified by FTIR. The shift in absorption edge to longer wavelength (from 387.5 to 418.9 nm) and higher absorption in the visible light region were observed. The results of photodegradation of the organic pollutant (methylene blue) using visible light irradiation (λ > 400 nm) suggest that the TiO2 photocatalyst was highly improved after doped with silver as compared with the undoped TiO2 photocatalyst.