Abstract: The phospholipase A2 was immobilized on the sodium alginate-chitosan supporter. The single-factor tests of immobilized condition were made through investigating the ratio of enzyme activity recovery, and then the results were selected by the response surface methodology. The optimal condition of the immobilized:the concentration of sodium alginate and chitosan were both 2. 0%, calcium ion concentration was 0. 25mol/L, glutaraldehude concentration was 0. 3%, the time of cross-linking was 7h, with these conditions, the ratio of immobilized enzyme activity recovery was 74. 8%. The immobilized PLA2 characterization:the optimal temperature for the immobilized PLA2 was 55℃, the optimal pH was 5. 0, and after seven times repeated reaction, the relative activity of immobilizaed phospholipase was greater than 54%. The result of SEM images showed that sodium alginate-chitosan supporter could better immobilized PLA2.