The analytical method for the determination of 19 prohibited components in hair-dyeing cosmetics using ultra-high-performance liquid chromatography-mass spectrometry was established.The sample was extracted with a volume fraction of 50% methanol-0.02 mol/L ammonium acetate solution using ice-bath sonication,and separated by Agilent Infinitylab Poroshell 120 SB-C18 chromatography column.Using acetonitrile-5 mmol/L ammonium acetate solution as the mobile phase for gradient elution,with a flow rate of 0.3 mL/min and a column temperature of 35 ℃,the 19 dyes were simultaneously detected by adopting a multi reaction monitoring(MRM) mode.The results showed that Solvent Green 7,Food Red 9,2-nitrophenylenediamine,and acid green 1 exhibited good linear relationships at 10~100 ng/mL.The remaining 15 components showed good linear relationships among 1~10 ng/mL,with correlation coefficients(R2) greater than 0.99.At three spiked levels,the average spiked recovery rates of 19 components were 82.4%~99.6%,with the relative standard deviations(RSD) of 1.2%~4.5%.This method features simple preprocessing,higher detection sensitivity and accuracy than liquid chromatography,and is suitable for the detection of 19 prohibited components in commercially available hair-dyeing cosmetics with different matrices.