Zinc sulfide (ZnS) is a kind of widely used optical thin film material, because of its wide light transmission area and easy deposition, it is widely used to make wide spectrum thin film devices. In this paper, terahertz time domain spectroscopy (THz TDS) is used to detect the terahertz spectral characteristics of zinc sulfide. Through experimental analysis and calculation of optical parameters, it is obtained that the transmittance of zinc sulfide in the 0.2-2.4 THz frequency band increases with the increase of frequency, and the refractive index is between 2.88-2.94; from the absorption spectrum, ZnS is There are absorption peaks at 0.23、0.39、0.81and 2.2 THz; and the real part of the dielectric constant is between 8.3-8.7, and the imaginary part is between 0-0.08. This research provides a reference for the application of zinc sulfide materials in the terahertz frequency range.