Abstract: The 1 g of sample was taken, and 10 μg · L⁻¹ mixed isotope internal standard solution, 10 mL of acetonitrile, 1 mL of water, and 0.5 g of sodium chloride were added. After homogenizing for 2 min, sonicating for 30 min, and centrifuging for 10 min, 2 mL of n-hexane was added into the supernatant, and the mixed solution was shaken for 5 min, and settled until the solution was separated into layers. Then 200 mg of N-propylethylenediamine (PSA), 200 mg of C₁₈, and 1 500 mg of anhydrous magnesium sulfate were added into the lower phase in sequence, and the mixture was shaken for 5 min, and centrifuged for 10 min. The 1 mL of supernatant was taken, and blown to near dryness at 25 ℃ by nitrogen. The residue was re-dissolved by 1 mL of ethyl acetate, and passed through a 0.22 µm PTFE needle filter, and the filtrate was analyzed by gas chromatography-tandem mass spectrometry. N-Nitrosamines were separated on HP-INNOVAX chromatographic column under programmed temperature conditions, ionized by electron impact ion source, detected in multiple reaction monitoring (MRM) mode, and quantified by isotope internal standard method. It was shown that linear relationships between the mass concentrations of 12 N-nitrosamines and response value ratios of the targets to internal standards were kept in definite ranges, with detection limits (3S/N) in the range of 0.17-0.66 µg·kg⁻¹. Test for recovery was conducted on 5 types of cosmetic blank matrices at spiked levels of 5, 20, 100 µg·kg⁻¹, giving recoveries in the range of 81.6%-117%, and RSDs (n=6) of the determing values in the range of 1.2%-4.8%. The proposed method was used for the analysis of 5 types of cosmetics samples on the market, and 12 N-nitrosamines were not detected.