Abstract: We produced the animal model of the early myocardial infarction (5 min to 24 h) by ligating the left anterior descending coronary artery of-rats. The immunohistochemical methods (PAP) of myoglobin antibody were performed to observe the myoglobin defects of myocytes in infarcting area of rat hearts. The results demonstrated that: Slight imcomplete myoglobin defects in few myo-cytes of infarcting area were noted at 30 min after coronary ligation. At 2-6h after coronary ligation, the limits of the myoglobin defects was extended and become ribbon strip or sheet in shape. At 10- 24h after ligation, the myoglobin defects of myoc-ytes in infarcting area attain total layer of myoc-ardium, the majority of myoglobin defects was complete and could be clearly differentieted from the non-infarcting area.