Objective: To analyze the trends on constituent ratio of non-ST-segment-elevation (NSTEMI) and ST-segment-elevation myocardial infarction (STEMI) and related in-hospital mortality in acute myocardial infarction (AMI) patients hospitalized in Beijing Anzhen Hospital from 2004 to 2014. Methods: This is a single-center, retrospective study. We reviewed all patients hospitalized for AMI in Beijing Anzhen Hospital from January 1 2004 to December 31 2014, and collected all related information including hospitalization stay, the type of AMI, revascularization and in-hospital mortality. We analyzed the trends of constituent ratio of NSTEMI and STEMI, and their in-hospital mortalities during the 11 years. Results: Data from a total of 23 864 patients with AMI, including 5 539 STEMI and 18 325 NSTEMI, were analyzed. Compared with STEMI patients, NSTEMI patients were older, less likely to be male (P<0.001), had higher prevalence of hypertension, hyperlipidemia, diabetes (P<0.001), and lower prevalence of smoking (P<0.001). Additionally, patients with NSTEMI were more likely to have prior history of MI (12.6% (695/5 539) vs. 7.4% (1 354/18 325), P<0.001) and coronary artery bypass graft surgery (2.7% (152/5 539) vs. 0.7% (124/18 325), P<0.001). The constituent ratio of NSTEMI was significantly increased during the observation period, rising from 15.8% (107/802) in 2004 to 35.7% (1 273/3 583) in 2014 (P value for trend <0.001). The in-hospital mortality of NSTEMI patients was significantly lower compared with those with STEMI (1.84% (102 cases) vs. 2.74% (502 cases), P<0.001). The mortality of both STEMI and NSTEMI were significantly decreased during the 11 years (both P value for χ² trend test <0.001). After adjusting for other risk factors, NSTEMI was independently associated with lower in-hospital mortality (OR=0.50, 95%CI 0.40-0.63, P<0.001). Conclusions In patients with AMI, the constituent ratio of NSTEMI versus STEMI is increased during the 11 years. The in-hospital mortality is decreased for both STEMI and NSTEMI patients in the past 11 years, and the in-hospital mortality rate of NSTEMI patients is lower than STEMI patients in this patient cohort during the observation period.