OBJECTIVE: To study the expression level of B7-H1 protein in the eyeball tissues of mice receiving corneal allograft transplantation and explore the role of B7-H1 protein in corneal immune privilege. METHODS: Mouse models of corneal allograft transplantation were established, and the corneal opacity and angiogenesis index was evaluated according to the Sonoda method. Eight weeks later, the mice were examined for the occurrence of graft rejection, and the expression level of B7-H1 protein in the eyeball tissues were detected by immunohistochemistry, using 8 normal mice as the control group. RESULTS: B7-H1 protein was expressed highly in the corneal and the choroidal/ciliary body in the normal control mice and the survived mice, but was absent in mice with graft rejection. CONCLUSION: B7-H1 protein may play a role in the immune privilege following corneal allograft transplantation in mice.