Abstract: As a combination of insect and fungus, Cordyceps ciecadae Shing was complicated and which had many pharmacological functions.In order to investigate the effects of different extraction solvents on the relative content and fatty acid composition of Cordyceps ciecadae Shing, samples were extracted by ultrasonic extraction in this study with seven different solvents, such as n-hexane, petroleum ether, dichlorometh- ane, chloroform, ether, ethyl acetate and acetone.The composition and relative content of fatty acids were detected with Capillary Gas Chromatography and Chromatography- Mass Spectrometry ( GC /MS) . Results showed that the composition and content of relative fatty acids from the extractions of seven solvents were not exactly the same. Fourteen acetic acid, fifteen acid, sixteen acid, palmitic acid, stearic acid, oleic acid and linoleic acid were detected to all seven extractions.The content of unsaturated fatty acid in the extractions of seven different solvent accounted for more than 81.5% of total fatty acids.