We employ TiO2 single-crystal films as a substrate and use a photochemical deposition method to prepare Ag-doped and Ag/N co-doped TiO2 single-crystal films. We also investigate the optical and magnetic properties of the samples using various measurements. No diffraction peaks related to silver oxide appear in the X-ray diffraction (XRD) spectra, which implies the existence of Ag atoms in Ag-doped TiO2 single-crystal films. X-ray photoelectron spectroscopy (XPS) spectra indicate the existence of Ti4+ and Ag degrees in Ag/N co-doped TiO2 single-crystal films. It is found that Ag is deposited on a TiO2 single-crystal film surface in the form of Ag particles. Meanwhile, Ag particles can slightly enhance ferromagnetism in Ag-doped TiO2 single-crystal films compared with the TiO2 single-crystal film sample. Oxygen vacancies and Ag particle synergy influence ferromagnetism in Ag/N co doped TiO2 single-crystal films.