CdSe/CdS quantum dots(CdSe/CdS QDs) were prepared using thioglycollic acid(TGA) as stabilizer.A method was established for the rapid determination of cyromazine(Cyr) residues in pepper,cowpea,balsam pear,cucumber and cherry tomato using the CdSe/CdS QDs as a fluorescence probe,based on the phenomenon that the enhanced fluorescence of CdSe/CdS QDs was observed in the presence of Cyr.Experimental conditions for the determination of Cyr in five vegetables were optimized,including concentration of QDs,pH value,reaction time and coexistence substances.Results showed that the emission wavelength(λem) for CdSe/CdS QDs was 580 nm when the excitation wavelength(λex) was set at 481 nm.Under the optimum conditions,the established method exhibited a good linear in the range of 5.0-120 nmol/L with correlation coefficients(r) not less than 0.999 1.The limits of detection(LOD,S/N=3) and limits of quantitation(LOQ,S/N=10) were 0.8-1.4 nmol/L and 2.4-46 nmol/L,respectively.Recoveries at three spiked levels of 4,40,100 μg/kg ranged from 82.5% to 108% with relative standard deviations(RSD,n=3) not more than 6.9%.With the advantages of high selectivity,good sensitivity and simple operation,the method was successfully applied in the determination of Cyr in five real vegetables.