Background and aim of the study: Elderly patients are more likely to have adverse complications after coronary artery bypass grafting (CABG). There are few studies on the risk factors for acute kidney injury (AKI) after surgery in elderly patients, especially in the Asian population. This study retrospectively analysed the risk factors for AKI in Chinese elderly patients after CABG and established a risk prediction model to detect these risk factors early and take active intervention measures. Methods: A total of 432 patients were included in this study from 2018 to 2019. AKI was defined according to the Kidney Disease Improving Global Outcomes (KDIGO) criteria. The patients were divided into an AKI group and a non-AKI group. Multivariate logistic regression analysis was used to screen out the factors with p < 0.05. Results: Out of 432 patients in the study, 119 (27.5%) developed AKI. The estimated glomerular filtration rate (eGFR), ≥3 coronary anastomoses, preoperative intra-aortic balloon pump (IABP) implantation and prolonged ventilation time were independent risk factors for AKI. The area under the ROC curve was 0.702 (95% confidence interval (CI) [0.643-0.761], p < 0.001). Conclusions: The eGFR, ≥3 coronary anastomoses, preoperative IABP implantation and prolonged ventilation time are independent risk factors for AKI in elderly patients undergoing coronary artery bypass grafting. Early discovery of these risk factors and the implementation of appropriate intervention measures are useful to reduce the occurrence of AKI after CABG and improve the prognosis of patients.