A rapid analytical method was developed for the determination of three isothiazolinone reservatives,i.e2-methyl-4-isothiazoline-3-one(MI),5-chloro-2-methyl-4-isothiazoline-3-one(CMI) and 1,2-benzothiazol-3-one(BIT) in children's color clay modeling toys by high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS).The sample was ultrasonically extracted with methanol,then filtrated after centrifugation,and finally separated on a Kinetex C18 column(100 mm×3 mm，2.6 μm) by gradient elution with methanol and water as mobile phases at a flow rate of 300 μL/min.The sample was analyzed by HPLC-MS/MS in multiple reaction monitoring(MRM) mode,and quantified by the external standard method.Results showed that there were good linear relationships for three analytes in the concentration range of 1.0-100.0 μg/L with correlation coefficients(r) not less than 0.999 0.Average recoveries for the analytes ranged from 80.2% to 109%,with relative standard deviations(RSD,n=5) of 1.3%-7.0%.The limits of detection(LOD) for MI,CMI and BIT were 10,10 and 20 μg/kg,and the limits of quantitation(LOQ) were 30,30 and 60 μg/kg,respectively.