Aim To investigate the clinical features and therapeutic efficacy of thrombolytic therapy of acute myocardial infarction(AMI) in young patients and older patients. Methods 24 patients ≤45 years of age with a diagnosis of AMI,were received thrombolytic therapy after the onset of AMI,and assigned to the young group.40 consecutive patients aged 50～70 years old were selected as the control group.The patient's cardiovascular history,risk factors(smoking,hypercholesterolemia,hypertension,diabetes mellitus,and family history) and therapeutic efficacy of thrombolytic therapy were recorded and analysed. Results The percentage of male in young group were higher than in older group(P<0.01).The percentage of smoking and family history in young group were higher than in older group(79.2% and 45.8% vs 40.0% and 12.5%,P<0.01).The percentage of hypertension and diabetes mellitus in older group were higher than in young group(60.0% and 40.0% vs 16.7% and 12.5%,P<0.05).The history of angina pectoris in young group were shorter than in older group(324±576 days vs 928±1 846 days,P<0.001).The patients of chest pain in 30 days and 12 hours in young group were much more than in older group(62.5% and 41.7% vs 10.0% and 5.0%,P<0.001).The initiating time of reperfusion had no significant difference in two groups,but the recanalization rate of coronary artery was higher in young group than in older group(75.0% vs 50.0%,P<0.05). Conclusion Smoking and family history were the most common risk factors among young patients.The clinical history of young patients was shorter than older patients.The therapeutic efficacy of thrombolytic therapy in young patients was more excellent than in older patients.