The invention relates to a method for determining volatile nitrosamines in cosmetics by gas chromatography-mass spectrometry or mass spectrometry. The method is accurate and reliable, and the detection limit, the recovery rate and the precision meet the requirement. The invention establishes a method capable of simultaneously determining 10 types of volatile nitrosamines in the cosmetics by gas chromatography-tandem quadrupole mass spectrometry. The method is accuracy, quick and has high sensitivity, and can provide the scientific basis and the technical supports for the nitrosamine contamination monitoring and the product quality control of the cosmetics.