We report that results of investigation of the ZnS nanoparticles were synthesized by solid state reaction method at different annealing temperature (350 °C, 400 °C and 450 °C). The structural, functional, morphological and optical properties were characterized by using X-ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy, UV-Vis spectroscopy, photoluminescence (PL) spectroscopy and scanning electron microscopy (SEM) with energy dispersive X-ray analysis. XRD patterns confirmed to the ZnS nanoparticles have cubic crystal structure and crystalline nature. The FTIR spectroscopy shows the bonding nature and presence the metal oxide nanoparticles. The blue shift absorption was observed from the UV-visible spectrum. The photoluminescence spectra showed a two emission peaks corresponding to blue-green emission. A SEM photograph shows the spherical shaped nanoparticles and the elements Zn and S alone are identified from EDS.