Amylase is a digestive enzyme secreted by the pancreas, which is excreted into the duodenum via the pancreatic duct with pancreatic juice. In clinical practice, urinary amylase is mainly used for the diagnosis of pancreatitis, and its normal value is 80-300 U/L. If the test result exceeds 300 U/L, it can be considered as elevated urinary amylase. Elevated urinary amylase is usually seen 12 hours after the onset of acute pancreatitis and continues to peak for 1-2 weeks, before gradually returning to normal. Serum amylase, on the other hand, begins to rise 2-12 hours after the onset of the disease and begins to decline at 48 hours, lasting slightly shorter than urinary amylase for 5-7 days, and usually returns to normal for 3-5 days. Although elevated urinary amylase can be used as an auxiliary diagnostic basis for pancreatitis, it is not a complete diagnosis. This is because elevation of this indicator can also be seen in diseases such as pancreatic duct obstruction, pancreatic cancer, pancreatic injury, acute cholecystitis, gastric ulcer and mumps. In addition, in severe pancreatitis, due to severe necrosis of pancreatic cells and reduced pancreatic secretion, the patient’s blood and urine amylase will not necessarily be elevated. Therefore, the determination of the severity of pancreatitis is not based on blood and urine amylase, but should be combined with blood biochemistry, abdominal CT, hepatobiliary, pancreatic and splenic ultrasound and pancreatic MRI to clarify the severity of the disease, and then carry out targeted treatment.