The invention discloses a method for detecting acrylonitrile in cosmetics by using the gas chromatograph-mass spectrography, which comprises the followings steps of: adding methanol in a sample to be measured, ultrasonically extracting, centrifuging an extract, taking the supernate, drying the supernate with nitrogen, dissolving the dried supernate with a 10-percent methanol aqueous solution, purifying with a hydrophilic and lipophilic solid-phase extraction column, eluting the hydrophilic and lipophilic solid-phase extraction column with methanol aqueous solution of 80-percent volume percent, dehydrating the obtained eluent, concentrating, filtering the eluent with a filter membrane, and carrying out gas chromatogram-mass spectrum measurement, wherein the chromatographic column of the gas chromatogram is of bonding/cross-linked polyglycolic stationary-phase, the specification is 60m*0.25mm*0.50Mum, the temperature of the chromatographic column is increased in a programmed way, is maintained at 60 DEG C for 3 minutes, then increased to 100 DEG C by the increase rate of 4 DEG C/min and maintained at 100 DEG C for 2 minutes, and increased to 220 DEG C by the increase rate of 20 DEG C/min, the samples are fed in a split way, and the split ratio is 10 to 1. The method for detecting acrylonitrile in cosmetics by using the gas chromatograph-mass spectrography is fast, and has low detection limit and high recovery rate.