Objective To investigate the protective effects of emulsified isoflurane induced preconditioning on ischemia-reperfusion injury in rabbit hearts in vivo. Methods Thirty-two healthy rabbits of male weighing 2 kg2.5 kg were anesthetized with intramuscular Ketamine 70 mg/kg. The animals PaCO2 was maintained at 35 mmHg45 mmHg.The animals were randomly allocated to one of 4 groups of 8 animals in each group:control group received no pretreatment(C);and three groups were pretreated with lipid vehicle(L),isoflurane(I) and emulsified isofiurane(EI). Each group was subjected to 1 h occlusion of left anterior descending artery followed by 3 h reperfusion. The change of haemodynamics parameters was observed. Results There were no statistically significant different in HR,MAP,cardiac output (CO),left ventricular systolic pressure(LVSP),the maximum rate of left ventricular systolic pressure(+dp/dtmax ),left ventricular end-diastolic pressure(LVEDP)and rate-pressure products(RPP) among all groups during ischemia and early reperfusion period. LVSP in control group and lipid vehicle pretreatment proup were much lower while LVEDP higher than that in all precondition proups during the late reperfusion period(P<0.05),the other haemodynamics parameters were no statistically significant different(P>0.05).Conclusion Emulsified isoflurane-induced preconditioning as isoflurane significant myocardial protection against ischima-reperfusion injury in vivo rabbit hearts.