Bioartificial pancreas(BAP) made up of rat islet, agarose and collagen was developed in this experiment to cure the diabetes mellitus and prevent immune rejection of the islet xenograft. The insulin secretion function, immunoprotection and effect of BAP on the treatment of diabetes mellitus in mice were investigated. The results showed that the BAP maintained the insulin secretion function of islet, decreased the immunogenicity of islet xenograft and normalized the metabolic disturbances of carbohydrate in diabetic mice. These indicate that the BAP composed of the islet, agarose and collagen is an alternate approach to therapy for diabetes mellitus and to remission of immune rejection of the islet xenograft.