Mn-doped ZnS quantum dots capped with 3-Mercaptopropionic (MPA) were facilely synthesized as the ratiometric fluorescent (I590nm/I458nm) probe in aqueous solution for curcumin. Curcumin was found to be able to cause the defect-related fluorescence quenching of the probe at 458nm and the orange transition emission of the probe at 590nm changing negligibly by triggering the ratiometric change with variation of curcumin concentration. The MPA assemblied Mn-doped ZnS QDs has been developed for simple, sensitive and non-toxicity detection of curcumin. Under the optimized conditions, the response to curcumin allowed for a linear range from 0.16 to 16.9 µM with the detection limit 37 nM. The developed method was successfully applied to the detection of trace curcumin in urine samples with recoveries 97.73–109.73%.