Abstract: Determination with gas chromatography/flame ionization detector(GC/FID) for dioxane in cosmetics was developed.The cosmetics were extracted with water and dioxane was dissolved completely.1.0 g sodium chloride was added,producing "salting-out" effect,to increase the concentration of dioxane in headspace bottles.The cosmetics were mixed with water for 40 min at 70 ℃,then made gas-liquid balance state.The upper clear gas was injected into gas chromatography(GC) for detection.Programmed temperature was adopted,retention time of the chromatogram could be applied for qualitative analysis,and external standard was used for quantitative analysis.The quality and the quantity of the sample were confirmed further by gas chromatography-mass spectrometry.The result indicated good accuracy.The recovery rates of the dioxane were 98.8%108.5%.The RSDs of the dioxane were 2.95%-7.61%.The low detection limits of the method were 2.5 mg/kg.