Abstract: With the raw material of euphausia superba powder, the purity of the refining phosphatidylcholine gained by ethyl alcohol extraction and separation and purification reached 90.8%, then the refining phosphatidylcholine was used as raw material and phospholipase A₂ was used to catalyze the fatty acid hydrolysis of Sn-2 position of phosphatidylcholine in supercritical CO₂ system to make the fish oil DHA to Sn-2 position and form the DHA-PC with high DHA contents.Meanwhile, the effects of different parameters on the reaction were surveyed.The results showed that, the best additive amount of immobilization phospholipase A₂ was 15% ( occupied the total substratio) , the best enzymolysis was 6 h, the best enzymolysis temperature was 55 ℃, the best enzymolysis pressure was 12 MPa, respectively.Under such condition, the DHA binding ratio of euphausia superba phosphatidylcholine could reach 62.3 mol%. And it could be concluded that immobilization phospholipase A₂ is highly viable for phosphatidylcholine modification to prepare DHA-PC.