Abstract: A method of high performance liquid chromatography-tandem mass spectrometry was proposed for the simultaneous determination of 5 persistent, bioaccumulative and toxic (PBT) substances in toys. The coatings, plastics, and textiles of toys were collected and treated in accordance with ISO 8124-3:2020, and an aliquot (1 g) was taken, and mixed with 10 mL of toluene. After sealing, ultrasonic extraction was performed at room temperature for 30 min. The supernatant was taken and passed through a 0.45 μm filter membrane, and the filtrate was analyzed by high performance liquid chromatograph-tandem mass spectrometer. In the chromatography analysis, Agilent Poroshell HPH-C₁₈ column was used as the stationary phase, and mixed solutions composed of methanol and 0.1% (volume fraction) acetic acid solution at different volume ratios were used as the mobile phase for gradient elution separation. In the mass spectrometry analysis, ESI⁺ and MRM modes were used for scanning, and external standard method was used for quantification. It was shown that linear relationships between values of the mass concentration of 5 PBT substances and the peak area were kept in the range of 0.005-0.2 mg·L^-1, with detection limits (3S/N) in the range of 0.010-0.078 mg·kg^-1. Test for recovery was made according to the standard addition method, giving recoveries in the range of 85.7%-105%, and RSDs (n=6) of the determined values were not greater than 7.0%.