Abstract: Objective To analyze the coronary lesions and clinical features in AMI(both STEMI and NSTEMI) patients among different age groups. Methods The clinical data of 547 patients with AMI who admitted in the Second Hospital of Tianjin Medical University during January 2011 to December 2017 were retrospectively analyzed. The patients were divided into youth group (18 to 65 years old, n=176), middle-aged group (66-79 years old, n=176) and old group (80 to 99 years old, n=158). General information, laboratory examination results, Gensini score, infarction areas and coronary artery lesions were compared among three groups. Results The average age of 547 AMI inpatients enrolled was 68.5±12.8 years old. Women in the youth group were the least in the three groups（P＜0.01）. And the smoking rate of the old group was the lowest, while the middle-aged group was lower than that of the youth group（P＜0.01）. And there was no significant difference in the proportion of diabetes mellitus and hypertension among three groups（P＞0.05）. There was statistically significant difference in BUN, AST, WBC, NEU, RBC, Hb, PLT, LDL, HDL, TG and TC in the three groups, respectively(P＜0.01), while there was no statistically significant difference in SCr and ALT（P＞0.05）. The Gensini score was higher in the old group than in the other two groups, and the elderly with a score of more than 80 points were significantly richer than the youth and middle-aged groups（P＜0.01）, but the difference between the latter two groups was not statistically significant（P＞0.0167）. Most of patients in youth group were single vessel or two vessels disease, while middle-aged group and the old group were mostly multivessel disease. There was significant difference in the proportion of anterior wall and posterior wall infarction among the three groups（P＜0.01）, but there was no significant difference in inferior wall, lateral wall and right ventricular infarction（P＞0.05）. Conclusion There is significant difference in coronary lesions and clinical features of patients with acute myocardial infarction in different ages. And appropriate prevention and treatment should be selected for patients with myocardial infarction in different ages.