Aim To evaluate the cardiovascular risk factors of young patients with acute myocardial infarction and the influence on coronary artery disease. Methods 36 consecutive patients ≤45 years of age with a diagnosis of acute myocardial infarction, who were performed coronary angiography within 3 months after the onset of acute myocardial infarction, were assigned to the young group. We selected 50 consecutive patients aged 50～70 years old during the same time as the control group. The patient's cardiovascular history, results of coronary angiography and risk factors (smoking, hypercholesterolemia, hypertension, diabetes mellitus, and family history) were recorded and analysed. Results 91.7% were male in young group versus 72.0% in control group. The percent of smoking, family history, and hypercholesterolemia in young group were 83.3%, 47.2%, and 44.4%, respectively. The percent of hypertension, diabetes mellitus, smoking, and hypercholesterolemia in control group were 54.0%, 42.0%, 40.0%, and 38.0%, respectively. As a culprit artery, the prevalence of left anterior descending coronary artery, right coronary artery, and left circumflex coronary artery in young group were 58.3%, 38.9%, and 0 versus 56.0%, 42.0%, and 22.0% in control group, respectively. The incidence of singe, double, and triple vessel diseases in young group were 63.9%, 27.8%, and 8.3% versus 42.0%, 40.0%, and 18.0% in control group, respectively. The average risk factors of young group were 1.64±0.40 in singe vessel disease versus 2.78±0.56 in multi-vessel disease. Conclusions Smoking, family history, and hypercholesterolemia were the most common risk factors among young patients. Young patients had a higher frequency of singe vessel disease. There were no left circumflex coronary artery As culprit artery and no in-hospital deaths among young patients. In young patients, there were more cardiovascular risk factors in multi-vessel disease patients than in singe vessel disease patients.