Abstract: The changes of fatty acid composition in gonad of female and male Chinese mitten crab( Eriocheir sinensis) at different cooking time were investigated by gas chromatography- mass spectrometry.The results showed that long chain fatty acids were the main part of gonad,most of the amount was C18 ∶ 1n- 9c,and the amount of unsaturated fatty acids was larger than saturated fatty acids. During cooking,the fatty acids changed consistently.The saturated fatty acids showed a rising trend,the polyunsaturated fatty acids showed a downward trend,while the monounsaturated fatty acids changed fluctuating.The data indicated that C18∶ 3n-6 and C22∶ 1n-9were declined by 82.22% and 82.52% at the time of 60 min and 90 min,respectively compared with the raw sample. From the flavor point of view,the gonad of male Chinese mitten crab has great value in study and research.