Corneal transplantation has been considered a primary method for treatment of keratopathy. Corneal transptantation would bring immunological rejection although cornea belongs to an immune-privileged tissue owing to no vessels and lymphatic vessels. Immunological rejection is highly likely to occur in keratopathy patients who undergo large sizes of corneal transplantation or present with newly formed vessels in the center of implant. Many patients have to replace other implants because of immunological rejection. But severer immunological rejection caused by several corneal transplantations as well as rare donor source can not satisfy patients' requirement. Therefore, much attention has been paid to studies regarding drugs for immunologic protection following surgery. There have been many clinical studies confirming that the principle drugs against immunologic rejection, such as glucocorticoid and ciclosporin A, can not acquire satisfactory curative effects and concomitantly bring many adverse reactions. For this reason, many new immunosuppressive agents should be investigated. The method of drug combination has become an important research project for keratopathy physicians.