A gas chromatographic method was developed for the determination of free glycerol in crude glycerine without any derivative pretreatment.The sample was resolved with THF-water（3∶1）mixed solvents using diethylene glycol diethyl ether as internal standard,and was directly separated on an HP-5 column（30 m×0.32 mm×0.25 μm）.The influences of some important factors,such as solvent,internal standard,capillary column and injection volume were investigated.Under the optimal conditions,the standard curve of glycerol was linear in the concentration range of 0 -20 g/L,with correlation coefficient of 0.999 94.The relative standard deviations（RSDs,n=8） were in the range of 0.68%-0.91%.The spiked recoveries at three concentration levels ranged from 95% to 105%.Neither solvent nor internal standard applied in this method made chemical reaction with the ingredients of crude glycerine sample.This method was simple,rapid and accurate,and was suitable for the quantitative analysis of glycerol content in crude glycerine.