The purification of serum immunoglobulin in European eel( Anguilla anguilla) was carried out by using ammonium sulfate precipitation followed by column chromatography. The results showed that most of the eel serum Ig was precipitated at 30% to 50% ammonium sulfated saturation. Further purification by Sephacryl- S200 showed that the Ig presented in the first protein peak , and by Sepharose 4B the eel Ig existed at the second protein peak; the purif ied product ion from Sepharo se 4B were further separated by DEAE-52 column into two f ractions, and the Ig was found in the first f raction. The antibody activity of the productions stated above was proved by ELISA and Western-blot. SDS-PAGE showed that the heavy chain and light chain of the eel serum Ig were 68kD and 26kD respect ively.