To investigate the effects of Au-Ag co-doping on the microstructure and properties of ZnS thin films，ZnSAu∶Ag thin films with varying Ag contents were prepared using radio-frequency(RF)magnetron sputtering and were subsequently subjected to vacuum sulfurization annealing at 600℃ . Systematic characterizations were conducted using X-ray diffraction analysis， scanning electron microscopy， atomic force microscopy， UV-Vis spectroscopy， and Doppler broadening spectroscopy. The results demonstrate that all films exhibit a cubic phase with a preferred orientation along the(111)plane，and the introduction of Au/Ag significantly promotes a dense， vertical columnar growth. With increasing Ag concentration，the optical bandgap of the film decreases monotonically. Furthermore，microscopic defect analysis confirms that the large-radius Au/Ag atoms effectively occupy the Zn sites. Therefore，this co-doping strategy successfully fills the intrinsic zinc vacancies(VZn)and optimizes the lattice stoichiometry. Consequently，the bandgap is effectively reduced and the crystalline quality is significantly improved，providing a valuable reference for precise tuning of the optoelectronic properties of ZnS.