Abstract: The fatty acids components of medlar were studied by gas chromatography-mass spectrometry， using CH₃OH (10%H₂SO₄)-C₆H₁₄ as the methyl esterification solvent, the direct methyl esterification of fatty acids components in the Chinese material under the microwave-assisted conditions. According to GC/MS standard mass spectrometry database index combined with the regular patterns of organic spectrometry， the structure elucidation of the straight chain saturated fatty acids, single unsaturated fatty acids and double unsaturated fatty acids were analyzed. The novel method was established that can ascertain carbon atom number and double bond number in fatty acids using characteristic ions. The fatty acids components are quantified by the accuracy of area percent method. 21 fatty acids components are identified, accounting for 93.794% of the total components.