Objective To investigate the status quo and influencing factors of acute kidney injury (AKI) in elderly patients with acute myocardial infarction (AMI) after percutaneous coronary intervention (PCI). Methods The clinical data of 189 elderly AMI patients admitted to our hospital from June 2020 to June 2022 were retrospectively analyzed. All patients underwent PCI and were divided into AKI group (n=65) and non-AKI group (n=124) according to whether AKI occurred after surgery. General data, results of laboratory examination, and prognosis status were recorded among the patients. SPSS statistics 19.0 was used for data analysis. According to the data types, student′s t test or Chi-square test was performed for comparison between groups. Multivariate logistic regression analysis was adopted to analyze the related factors affecting AKI after PCI in the elderly AMI patients. Results Among the 189 elderly AMI patients, 65 patients were complicated with AKI (34.39%). The AMI group had significantly longer hospital stay and larger proportions of heart failure, infection, bleeding, automatic discharge and death than the non-AKI group (P<0.05). Multivariate logistic regression analysis revealed that diabetes mellitus (OR=3.766, 95%CI 2.031-6.982), cardiac function Killip grade (OR=3.043, 95%CI 1.966-4.712), white blood cell (WBC) count (OR=1.877, 95%CI 1.058-3.364) and N-terminal pro-brain natriuretic peptide (NT-proBNP) level (OR=2.590, 95%CI 1.386-4.765) were risk factors for occurrence of AKI in elderly AMI patients after PCI, and estimated glomerular filtration rate (eGFR, OR=0.470, 95%CI 0.327-0.676) was a protective factor. Conclusion The incidence of AKI is quite high in elderly AMI patients after PCI, and AKI will increase poor prognosis. For the patients complicated with diabetes mellitus and poor cardiac function, special attention should be paid to their treatment and nursing in clinical practice. In addition, baseline eGFR, WBC count and NT-proBNP level can be used to assess the risk of AKI in the patients.