Acute kidney injury (AKI) is a common critical condition with high mortality and poor prognosis. Currently, its diag-nosis relies on the increase in serum creatinine and the decrease in urine output. No specific therapy is available for it and renal replacement therapy is needed for severe patients. The AKI Guidelines and Consensus, updated four times from 2002 to 2017, exerted positive effect on early identification of AKI patients. However, the present definition of AKI does not make a distinction between transient and persistent AKI. This paper reviewed the progress in their pathology, clinical manifestations, diagnosis and treatment.