ZnS nanoparticles and Mn2+-doped ZnS nanoparticles were prepared by a reverse micelle reaction system. In addition, ZnS and Mn2+-doped ZnS nanoparticles were modified with poly(vinyl alcohol) (PVA) and 1-dodecanethiol (C12H25SH). The average particle size of the ZnS sample is determined around 2.3 nm by using the well-known Scherrer equation, which is in accordance with the results obtained from UVvis and TEM analysis. Fluorescence intensity of the Mn2+-doped ZnS nanoparticles increases with increasing Mn2+ content compared with undoped ZnS nanoparticles, and coating PVA can also make fluorescence intensity increase. Different Zn2+/S2- or C12H25SH/Zn2+ can affect intensity of PL emission peak and its position, which is discussed in this paper.