In order to obtain high-performance transparent dielectric thin films， nanocrystalline zinc-rich ZnS films were prepared on glass substrates by radio frequency magnetron sputtering with a ZnS ceramic target at room temperature， and the effect of the radio frequency power on the structural， surface morphology and optical properties of the films were studied using X-ray diffraction， field emission scanning electron microscopy， micro-Raman spectroscopy， ultraviolet-visible spectroscopy and spectroscopic ellipsometry. It is found that the radio frequency power has an important impact on the phase formation and crystallinity of the ZnS_X films. With the increase in the radio frequency power， the atomic ratio of zinc to sulfur， intensity of the characteristic Raman peak and refraction index first increase and then decrease， the optical band gap of the film deceases from 3.86 eV to 3.76 eV systematically. Among the various radio frequency power values investigated， 150 W is optimal for the growth of highly crystalline ZnS_X films with the cubic phase， the ratio of Zn/S of film is 1.23 close to the standard stoichiometric ratio， the average transmittance is more than 80% at visible light， and the optical refractive index of ZnS_X film is 2.03 at 550 nm.