Abstract： The eftect of Rapamycin (RPM) as immunosuppressant was evaluated in heart allotransplantation in SD、Wistar rats of the three groups.Experimental group was give RPM,control groups included untreated group and Cyclosporine (CsA)-treated group.The results showed RPM was a potent immunosuppressive agent which was superior to CsA in therapeutic effects.RPM had a strong immunosuppressive effect and significantly prolonged allograft heart survival.RPM not only prevented allograft rejection,but also reversed the ongoing allograft rejection.PRM had a good syncrgism with CsA in trcating graft rcjcction.