Objective To construct an animal model of vascularized iliac bone transplantation which could establish the immune chimerism.Methods The experiment was divided into three groups.In experiment group we slected the male SD rats as donors and the female SD rats as recipients.Then the experiment group was performed the improved vascularized ilium transplantation operation.The positive group was male SD rats without handling.The negative group was female SD rats without handling.On the twenty-eighth day after surgery, the rat SRY gene was detected by PCR.Dynamically monitoring the changes of the ratio of CD4+/CD8+ T cells by flow cytometry after operation.Dynamically monitoring the changes of the levels of serum IL-2 by enzyme linked immunosorbent assay after operation.Imaging and pathology were used to detect the transplanted iliac bone.Results Ten transplantations were performed in the experiment group and 7 flaps survived with a successful rate of 73 ％.SRY gene was detected in female rats that receive the male rats'iliac bone transplantation by PCR in the experiment group.After Micro-CT scanning and three-dimensional reconstruction, it showed that the transplanted iliac bone mineral density was decreased.Comparing rats that establish the chimerism with normal rats, the ratio of CD4 +/CD8 + T cells and the levels of serum IL-2 had no difference.Pathological results showed that the transplanted iliac bone of rats with chimerism were normal and the rats without chimerism were necrotic.Conclusions From the improved vascularized ilium transplantation operation, we successfully detected the SRY gene in female rats which received the male rats' iliac bone transplantation.It proved that the improved vascularized ilium transplantation operation could establish the chimerism.Through the immunosuppressant, the immune status of the rat after operation was well.