The aim of this study is to investigate fatty acid and lipid class variation in the ovary of natural spawn-ing blue crab,Callinectes sapidus in the second gonad development.In the trial,35 crabs' lipid classes were ana-lyzed by Iatroscan TLC/FID and 19 crabs' fatty acids were analyzed by Agilent 6890 gas chromatograph.The changes of main fatty acids and main lipid classes of blue crab in second gonad development were monitored.The main fatty acids were those more than 4% of total fatty acids,and the main lipid classes were those more than 5% of total lipid.There were eight kinds of main fatty acids(C16:0,C16:1n7,C22:6n3,C18:0,C20:4n6,C18:1n7,C18:1n9,C20:5n3) and four kinds of lipid classes(CHO,TG,FFA,PL).The results showed that the percentage of C16:0,C16:1n7,C22:6n3 and TG increased in relation to GSI,and they had significant relationship with GSI(P0.05).However,the per-centage of C18:0,C20:4n6 and CHO decreased in relation to GSI,and the relativity was significant(P0.05).There was no significant evidence that C18:1n7,C18:1n9,C20:5n3 and PL varied in relation to GSI(P0.05) except for FFA(P0.05).The conclusion obtained by data above is that ARA(C20:4n6),CHO and DHA(C22:6n3) are important in gonad development of blue crab.So they should be taken into account in designing feed formulas for parental crabs.The data provided scientific reference for feed formulation for parental blue crabs.