The Mndoped ZnS nanocrystallines were synthesized by the hydrothermal method.The microstructure and photoluminescent property were investigated by Xray diffraction (XRD),scanning electron microscope (SEM), viberating sample magnetometer (VSM) and photoluminescence (PL) spectra, respectively. The results showed that the ZnS∶Mn nanocrystallines were the spherical zinc blende structure with the grain size of about 20 nm. In the role of an external magnetic field, the magnetization of the ZnS∶Mn nanocrystallines was enhanced with the increase of the Mn doped concentration,The intensity of the emission spectrum of ZnS∶Mn nanocrystallines was the strongest when the Mn doping concentration x(Mn)=2%;while x(Mn)=10%, the intensity of the emission spectrum decreased obviously. The concentration quenching caused by the ions collide with each other as well as the large number of defect introduced by high concentration Mn maybe the causes of this phenomenon.