This is one of the important objective indexes for the diagnosis of acute pancreatitis, but it is not a specific diagnostic method. In the early stage of the disease, when there is embolism of pancreatic blood vessels and some hemorrhagic necrotizing pancreatitis, it may not increase because of the serious damage of pancreatic tissue. Sometimes, in the case of shock, acute renal failure, pneumonia, mumps, perforated ulcer and intestinal and biliary tract infections, amylase can also increase. Therefore, when there is an increase in amylase, it is necessary to combine the medical history, symptoms and signs to rule out the increase in amylase caused by non-pancreatic diseases in order to diagnose acute pancreatitis.