Abstract: Arginine deiminase (ADI) was immobilized on 7 kinds of ion-exchange resins, in which D301-G was the best material for the immobilization. And the enzyme was immobilized by cross-linkage of glutaraldehyde. After single-factor experiments, the optimal immobilized conditions were enzyme load of 156 U/g resin, 4-hour absorption at 28 ℃, p H4.0, the glutaraldehyde concentration of 0.07% and 4-hour cross-linking action at 4 ℃. Besides, the activity recovery yield of the immobilized enzyme reached above 85%.The optimal temperature and p H of the immobilized enzyme was 50~60 ℃ and 5.0~5.5, respectively, and it presented higher thermostability and higher Kmthan that of the free enzyme. The immobilized enzyme retained 57.7% of its initial enzyme activity after reuse for eight times. The results showed the enzyme immobilized which provided a technical basis for the application of arginine deminase industrially continuously producing citrulline.