Objective: To evaluate the effects of propofol on metabolism and ultrastructure of acute ischemia-reperfusion myocardium in an open-chest canine model. Methods: Eighteen hybrid dogs(11-14kg) were divided randomly into 3 groups: NS group (normal saline), 2ml/(kg.h)； HP group (high-dose propofol), 11.2 mg/(kg.h)；LP group (low-dose propofol), 5.6mg/(kg.h). These dogs were subjected to a 90min left anterior descending coronary artery (LAD) occlusion followed by 200 min of reperfusion. Before administration, 60min after administration, 90min after occlusion and 60, 120,180 min after reperfusion, lactate dehydrogenase(LDH) and superoxide dismutase(SOD) in great cardiac vein were detected. 200min after reperfusion myocardial ultrastructure was examined by electronic-microscope. Results: Compared with the value in HP and LP group, LDH in NS group was significantly higher, SOD was significantly lower(P<0.05) during reperfusion. Impairment of myocardial ultrastructure was most severe in NS group. Conclusion: Propofol can reduce myocardial ischemia-reperfusion injury in a canine model with its anti-oxidation and protection of chondriosome.