ZnS thin films were prepared on glass substrate by RF magnetron sputtering technique.The quality of ZnS films formed at different deposition pressures,annealing temperatures and substrate temperatures were studied.The change of the film microstructure was analyzed by XRD and the lattice stress was evaluated.The spectral transmittance was measured by a spectrometer.From the spectrum,the band gap and Urbach energy were calculated.Scanning electron microscopy (SEM) was used to study the morphology of the surface of the sample.The result showed that there is big stress in the lattice when the substrate is at room temperature,and the value of stress increases with the pressure.After annealing at 300 ℃,the stress is minimal.When the substrate temperature is 350 ℃,the stress decreases,at the same time,ZnS films have good transmittance,and annealing at 300 ℃ improves the film quality.