Abstract: The sample is first acidified, followed by the derivatization with sulfuric acid-methanol, then separated and ionized with DB-WAX capillary column and electron ionization source. The components of the fatty acids of the mixture aliphatic sodium in the practical samples are qulitatively confirmed by comparing with retention time and mass spectrum of the standards. The relative contents of the various fatty acids are calculated using the square penks to normalizaion. The relative standard deviation(s r) is less than ±5%. This method is simple, accurate and reliable for the qualitative and quantitative analysis of the mixture aliphatic salts.