The diagnostic criteria for acute renal failure are that the patient has a progressive decline in renal function within 48 hours, the absolute value of blood creatinine elevation ≥ 26.4 μmol/L, or more than 50% higher than the basal value, and at the same time the patient is oliguric, with a urine output of less than 0.5 milliliters per kilogram of body weight per hour, and lasting for more than 6 hours. Acute renal failure is divided into the following types according to the etiology: 1. Pre-renal: generally caused by insufficient effective circulating blood volume and reduced renal perfusion, such as in various types of shock, which can lead to pre-renal renal failure; 2. Renal: generally caused by glomerulonephritis, renal interstitial disease, or renal vascular pathology resulting in renal parenchymal disease, which can lead to acute renal failure; 3. Post-renal: generally refers to urinary tract stones or urinary tract obstruction, resulting in postrenal renal failure. Acute renal failure patients, there will be obvious edema, pulmonary edema, dyspnea, heart failure and various types of arrhythmia, there will be gastrointestinal edema as well as toxins can not be excreted in a timely manner, resulting in patients with gastrointestinal symptoms, which are manifested as decreased appetite, abdominal distension, nausea, vomiting. Patients also have a tendency to bleed and are prone to various infections and blood clots. Therefore, patients with acute renal failure need to be diagnosed and treated promptly.