Epidemiological evidence suggests that the incidence of acute myocardial infarction (AMI) among people under 40 years of age has an increasing trend in recent years. Smoking, hypertension, diabetes mellitus, family history, and gender (male) are considered as classic risk factors for CHD, but the pathogenesis of CHD in young people is not exactly the same. Moreover, the relationship between the pattern of coronary artery disease and risk factors in young patients with acute myocardial infarction is inconclusive. In this study, we retrospectively studied the clinical data of 150 AMI patients treated in our hospital from January 2020 to May 2021. The patients were divided into the young group and elderly group according to the difference in age. The number of coronary artery lesions, the degree of coronary artery stenosis, the distribution dominance typing, the position of the lesions, and the presence of collateral circulation were observed and compared between the two groups. Multivariate logistic regression analysis was used to investigate the risk factors affecting coronary artery lesions in young patients with AMI. The results showed that the number of coronary lesions in young patients with AMI was mainly single-vessel, and the dominant type of distribution was mainly right dominant type. The stenosis degree is lighter than that of elderly patients, and the incidence of collateral circulation is lower than that of elderly patients, but the position of the lesions has no obvious regular. Smoking, staying up late, HDL-C, and LDL-C/ApoB were independent factors affecting the number of coronary artery lesions, and the changes of HDL-C and LDL-C/ApoB had an important influence on the degree of coronary stenosis in young patients. This provides a new idea for clinical treatment.