Abstract: Fatty acids were extracted from marine sediments of OKINAWA Troughin the eastern part of the East China sea. The complete fatty acid mixtureswere derivatised as methyl esters (FAME) using COCL-CH_3OH solution, theseFAME mixtures were isolated with thin layer chromatography (TLC) to getmono-fatty acids which were identified by GG-MS-DS usiug a flnnigan 4515equipped with a fused silica capillary column, fragment ious m/e 55, 69, 83,M-32, M-74 and M~+ were used as indicators for unsaturated fatty acid methylesters, fragment ion m/e 74, 87, 143, M~+ and relative retention time of GCwere used for the determination of saturated normal, iso, anteiso, 10-Methylisoprenoid fatty acid methyl ester. The results show that straight chainFAME were distributed with a series of C_(12): o to C_(30): o and branched chainwere ranged from i-C_(13): o to i-C_(19): o, ai-C_(15):o to ai-C_(17): o as well as isopr-C_(17): o and 10-MeC_(16): o and unsaturated FAME were recognized as C_(16): o toG_(19): o.