Objective To analyze the impact of preoperative resting heart rate (RHR) on the efficacy of percutaneous coronary intervention (PCI) and prognosis in the elderly patients with ST-segment elevation myocardial infarction (STEMI). Methods A total of 211 elderly STEMI patients admitted to the Wanbei Coal-Electricity Group General Hospital between January 2020 and January 2021 were included as the study subjects. According to the preoperative RHR level, the patients were divided into RHR1 group (RHR<60 times/min; n=43), RHR2 group (RHR:60-79 times/min; n=76), RHR3 group (RHR:80-99 times/min; n=55) and RHR4 group (RHR≥100 times/min; n=37). The case data of each group were compared. Blood flow grading and myocardial perfusion grading of Thrombolysis in Myocardial Infarction (TIMI) after PCI were recorded, and deaths and major adverse cardiovascular events (MACE) at 30 days and 1 year after PCI were counted. SPSS 19.0 was used for statistical analysis. Data comparison between two groups was preformed using t test orχ² test depending on data type. Cox proportional hazard regression was employed to analyze the relationship between preoperative RHR level and prognosis in the STEMI patients. Results There were statistically significant differences among RHR groups in the proportion of diabetic cases, systolic blood pressure, diastolic blood pressure, low-density lipoprotein cholesterol and neutrophil count at admission, proportion of cases with left ventricular ejection fraction ≤40%, myocardial infarction area and plasma N-terminal pro-B-type natriuretic peptide (P<0.05). There were statistically significant differences among RHR groups in TIMI blood flow grades and myocardial perfusion grades (P<0.05). There were statistically significant differences in the incidence rate of MACE and death rate within 30 days after PCI and at one year after PCI among RHR groups (P<0.05). Multivariate Cox proportional hazard regression analysis suggested that preoperative RHR≥100 beats/min was a risk factor for death (RR=3.985; P<0.001) and MACE (RR=6.091; P=0.013) within 30 days after PCI in the STEMI patients, and that preoperative RHR≥100 beats/min was a risk factor for death (RR=2.744; P<0.001) and MACE (RR=3.114; P<0.001) in STEMI patients at one year after PCI. Conclusion Preoperative RHR≥100 times/min will increase the risk of death and MACE in STEMI patients after PCI.