Fluorescence sensing of Tyr enantiomers was conducted by L-NAC-CdSe/CdS QDs. Water-soluble chiral L-NAC-CdSe/CdS QDs was synthesized by a one-step reaction. L-NAC-CdSe/CdS QDs demonstrated high selectivity for Tyr enantiomers. The impact of pH on the chiral sensing capacity of QDs/Tyr system has been studied. The recognition mechanism is studied via UV–visible absorption and CD spectra.