Abstract: The composition of amino acid and fatty acid in fertilized eggs and lost eggs of Eriocheir sinensis were determined with capillary gas chromatography and HPLC.The results showed that there was no difference in the contents of essential amino acid (EAA) and supplemental amino acid (SAA) among the fertilized eggs of Taihu population and Wenzhou population,and the lost eggs of Wenzhou population of Eriocheir sinensis,and the non-essential acid (NEAA),including Glu,Cys and Ser had some difference between the eggs of three groups. There were 16,13 and 14 kinds of fatty acids in fertilized eggs of Taihu population and Wenzhou population,and the lost eggs of Wenzhou population,respectively.Saturated,monounsaturated and polyunsaturated fatty acids represented 18.96%-23.09%,51.76%-62.65%and 14.27%-28.96% of total fatty acids in the eggs respectively.The major fatty acid in each group were C16∶0(14.97%-18.59%),C16∶1(12.07%-20.28%)and C18∶1(37.98%-41.21%).There was significant difference in the contents of fatty acid between the eggs of three groups. The C18∶2,C18∶3 of fertilized eggs of Taihu population were more than that of Wenzhou population,and the DHA of fertilized eggs of Taihu population was much less than that of lost eggs of Wenzhou population.There were no significant changes of C14∶n and C16∶n between the fertilized eggs and the lost eggs of Wenzhou population.The relation between the abortion and the contents of amion acid and fatty acid,and the contents of fatty acid which influence the survival rates were also discussed in this paper.