Abstract: Water-soluble ZnS：Mn²⁺ quantum dots（QDs） emitting at 573 nm were synthesized with gas-liquid phase method.Effect of Mn²⁺ concentration on fluorescence intensity of ZnS：Mn²⁺  QDs has been studied.It was found that fluorescence intensity gradually increased with the increase of Mn²⁺ concentration.When Mn²⁺ doping concentration was at 1%，the maximum emission intensity was achieved.If the Mn²⁺ concentration continued to be increased，the fluorescence would decrease.ZnS：Mn²⁺ QDs was characterized by transmission electron microscopy（TEM），X-ray diffraction（XRD），Infrared Spectroscopy（IR），UV-Vis absorption spectroscopy（UV-Vis），and photoluminescence（PL） emission spectroscopy.Results demonstrated that ZnS：Mn²⁺ showed strong yellow fluorescence.

Key words: ZnS：Mn²⁺ quantum dots （QDs）, Mn²⁺ concentration, fluorescence