In this paper,the fatty acid compositions of fish oils were analyzed and ox-idative property was evaluated. The result showed that the fatty acid composition varied greatly with fish. The content of PUFA(w3) of caplin oil,herring oil,mackeral oil menhaden oil was 11. 3%, 14. 3%, 21. 0%and 27. 6% respectively; the content of SFA was 17. 52%, 21.2%, 24. 12%and31. 15%; the content of MUFA was 62. 46%, 52. 9%, 40. 04%and 26. 26%. The content of EPA and DHA was about 15%-35%in anchovy oil,especially the DHA content (18- 44%)of anchovy oil in China was higher than EPAC13. 66%) and low content of C20,i and C22,1 But the DHA content of anchovy oil in South Africa,South Chile , North of Chile,Califor. US and Peru was lower than EPA. The content of SFA of fish oil increased with the storage and the content of PUFA in reverse. Temperature is an important factor affecting oxidation of fish oil.