Objective an experimental animal model of acute myoc ardial infarction (ANI) was established by opening chest and ligation of the left anterior descending (LAD) coronary artery． Methods a total of 20 rabbits were opened chest and ligated LAD under sterilization． Electrocardiogram (ECG) and myocardial-enzymes in blood serum were investigated． Results ECG of all rabbi t s showed normal before operation． Irmediately after and 1/2 hour after ligation , ST-segment elevated and ECG showed ambulatory changes for 7 and 9 rabbits respectively． Two hours after LAD ligation, the change of ECG for 2 rabbits wa s not typical and 2 of them died during experiment． Four weeks after operation, E CG of 18 rabbits showed the chest leads had pathologic Q waves． Twenty-four ho urs after LAD ligation, AST, LDH, LDH-1, CK and CK-MB in blood serum were significantly increased． There was significant difference compared with before operation (except LDH) (P<0. 0l)． Conclusions:The method was sim ple and well repeated． The formation of myocardial infarction was reliable and rabbits were maintained for a long time after operation． It provides a valuable animal mode l for the experiment study of coronary heart disease．