Objective To found one model of chronic myocardial infarction in rats. Methods The Wistar rats were anaesthetized by 10% hydro-chloro-aldehyde, then intubated through oral tracheal and performed left anterior thoracotomy between the region of third and fourth intercostal, finally ligated the left anterior descending coronary artery. Results The survival rate was 80.8% beyond 3 weeks. Conclusion This operation is easy to perform and has high success, and also has little damage to animals.