Objective, To evaluate the function of alginate poly-L-ysine membrane in protecting porcine to rat islet xenografts. Material and Methods. Newborn porcine islet-like cluster cells (ICC) were obtained by digesting pancreas with type XI collagenase. After 2-3 days' incubation, encapsulated ICC were formed through instrument. In vitro, insulin release and insulin stimulating test was performed. In vivo, encapsulated ICC were transplanted into streptozotocine-induced diabetic rats. Results, Unlike ICC only (insulin can be tested within 14 days) encapsulated ICC maintained insulin release at certain level for nearly 28 days. High insulin response to 16.7 mM glucose and 10 mM theophylline significantly differed from low insulin response to 5.6 mM or 16.7 mM glucose (P < 0.01). Extended survival of porcine ICC xenografts implanted in diabetic rats had been achieved by encapsulation. After transplantation, rats sustained normaglycemia for average 4 months. The capsules with ICC obtained from experimental group could be stained with neutral red. Insulin release of survival capsules with ICC in response to 16.7 mM glucose and 10 mM theophylline was 3 times more as compared to the insulin response to 5.6 mM glucose. Sections of encapsulated ICC (H&E) showed fairly good cell clusters and the membranes were generally free of fibrosis and host cell adherence. Conclusion, Artificial membrane can protect discordant islet xenografts from rejection.