Abstract: In order to find a new way to treat testosterone insufficiency,leydig cells of new born rats were seperated,cultured,microencapsulated and implanted into the intraperitoneal cavi ty of mice recipients.The results showed that the microencapsule membranee had a good permea bility to testosterone;leydig cells in the microencapsule were responsive to the stimulation of hCG;one month after transplantation,the blood testosterone levels in experimental and experimental control group were 1.16±0.28nmol/L and 0.60±0.10nmol/L,respectively.In the negarive control group,the testosterone level was below the sensitivity of the assay.It is indicated that the microencapsulation can diminish the immune reaction to the leydig cells after transpIantation,and that this approach will potentially lead to clinical application.