Acute renal failure (ARF) is one of the serious complications after cardiac surgery, but when ARF can be clearly diagnosed, the renal function is often already severely damaged, and the result is often difficult to treat and the prognosis is poor. Therefore, domestic and foreign scholars introduced the concept of acute kidney injury (AKI) to replace ARF, with the aim of early diagnosis and treatment at the stage when the glomerular filtration rate starts to decline or when the glomerular filtration rate is still normal but the kidney is already damaged, so as to avoid further deterioration of renal function. In our study, we found a high incidence of AKI after CABG, and the occurrence of AKI after surgery will increase the length of stay in the intensive care unit and postoperative hospitalization, which requires attention.