Objective To investigate the predictive value of age, creatinine and ejection fraction (ACEF) score for cardiac death and adverse cardiac events in patients over 75 years old with acute ST-segment elevation myocardial infarction (STEMI) within 1 year after percutaneous coronary intervention (PCI). Methods The clinical data of 432 STEMI patients undergoing PCI in the Dongnan Hospital from January 2015 to June 2020 were collected and analyzed retrospectively. According to their ACEF score before PCI, the patients were divided into low to moderate risk group (ACEF≤1.3 points, n=96) and high risk group (ACEF>1.3 points, n=336). The incidences of cardiac death and adverse cardiac events within 1 year after PCI were observed. Cox hazard proportional regression analysis was used to analyze the risk factors influencing the occurrence of cardiac death and adverse cardiac events within 1 year after PCI in the patients, and receiver operating characteristic (ROC) curve was drawn to evaluate the predictive value of ACEF score. SPSS statistics 20.0 was used for statistical analysis. Data comparison between 2 groups was performed using student′s t test, or Chi-square test depending on data type. Results The age was obviously older and the heart rate was significantly higher in the high risk group than the low to moderate risk group [(81.02±4.33) vs (78.94±3.05) years, (76.94±18.67) vs (71.36±16.84) times/min, P<0.05]. The low to moderate risk group had significantly higher left ventricular ejection fraction [(59.12±21.38)% vs (43.88±16.17)%, P<0.05] and better estimated glomerular filtration rate (P<0.05) than the high risk group. The rate of complete revascularization was statistically lower in the low to moderate risk group than the high risk group [10 cases (10.42%) vs 67 cases (19.94%), P<0.05]. But no remarkable differences were seen in other treatment-related parameters. Cox regression showed that ACEF score was an independent risk factor affecting cardiac death and adverse cardiac events within 1 year in patients (RR=1.557,1.626; P=0.000,0.000). The area under ROC curve predicted by ACEF score for cardiac death 1 year after PCI was 0.846, and the best cut-off point for diagnosis was 1.61. The area under the ROC curve for predicting adverse cardiac events was 0.891, and the best cut-off point for diagnosis was 1.47. Conclusion Preoperative ACEF score can predict cardiac death and adverse cardiac events within 1 year after emergency PCI in STEMI patients over 75 years old.