Objective To analyze the status of percutaneous coronary intervention (PCI) and prognosis in patients aged 75 years or older with acute ST-elevation myocardial infarction (STEMI). Methods The clinical data of 425 acute STEMI patients aged≥75 years admitted to our hospital from April 2009 to December 2018 were retrospectively analyzed. According to their treatment during hospitalization, they were divided into emergency PCI group (n=112), elective PCI group (n=80) and conservative treatment group (n=233). Their basic clinical data, treatment during hospitalization and incidence of complications were collected. All patients were followed up regularly every 1-3 months by clinical visits or phone interview till December 2019. SPSS statistics 26.0 was used for data analysis. Multivariate logistic regression was used to analyze the factors influencing the clinical decision-making strategy. Kaplan-Meier survival curve was drawn, and log-rank test was employed to analyze the differences in survival rates among the groups. Results The rates of emergency coronary angiography and emergency PCI were 31.5% (134/425) and 26.4% (112/425), respectively for the acute STEMI patients aged ≥75 years. Multivariate logistic regression analysis revealed that symptom-onset-to-treatment time (OR=0.841,95%CI 0.792-0.893;P<0.001) and initial Killip class ≥Ⅱ (OR=0.440,95%CI 0.238-0.814;P<0.01) were independent influencing factors of emergency PCI; age (OR=1.259,95%CI 1.129-1.405;P<0.001), creatinine clearance rate (OR=0.972,95%CI 0.952-0.993;P<0.01) and initial Killip class≥Ⅱ (OR=2.958,95%CI 1.420-6.163;P<0.01) were independent factors for elective PCI. The in-hospital all-cause mortality was 13.4% (15/112), 3.8% (3/80) and 18.9% (44/233), respectively in the emergency PCI, elective PCI and conservative treatment groups, with significant differences among them (P<0.05). The incidence of ventricular fibrillation was statistically lower in the elective PCI group than the emergency PCI group [0.0% (0/80) vs 8.9% (10/112), P<0.05]. During a median follow-up of 31 (12～53) months, the cumulative survival rate was remarkably lower in the conservative treatment group than the emergency and elective PCI groups [44.6% (104/233) vs 71.4% (80/112), 78.8% (63/80); all P<0.05]. Conclusion Elderly STEMI patients aged ≥75 years have a lower rate of undergoing emergency PCI. Symptom-onset-to-treatment time, advanced age, impaired cardiac and renal functions are associated with clinical decision-making strategy. The patients undergoing PCI will achieve significantly higher short- and long-term survival rates than those taking conservative management.