Acute pancreatitis is one of the common acute abdominal conditions that can occur at any age and social class, and its clinical manifestations range from mild, momentarily self-limiting abdominal pain to acute, fatal abdominal pain. Seventy-five to 85 percent of patients with acute pancreatitis are mild and can usually be cured with appropriate supportive therapy. The incidence of acute severe pancreatitis accounts for about 20% of all cases of pancreatitis, and its clinical course can be very aggressive, with rapid development, 65% complication rate, 30-50% mortality, and a long course of several months. In the last decade or so, advances in diagnostic and therapeutic measures have not only improved the efficacy of the disease, but have also confirmed the status of surgical treatment of severe pancreatitis. Severe acute pancreatitis is manifested at the onset of the disease, from mild acute pancreatitis to severe acute pancreatitis rarely develops slowly; therefore, Ranson (1974) proposed 11 parameters to determine the prognosis of AP, and later the APACHE II scoring system appeared to determine the prognosis of AP. The Ranson parameters began to be replaced by the APACHE II score in the 1990s. Because the Ranson parameters need to be evaluated 48 hours after admission to hospital, in fact, there may be significant changes in the condition after 48 hours of admission, and it is possible that the condition may become better or worse. APACHE II has been widely used in AP and acute intra-abdominal infections and is still respected today. In fact, after the patient is admitted to the hospital and the fluid-electrolyte imbalance is corrected and the patient is treated symptomatically, the A score may have decreased, while the B and C scores are fixed and the total score is still decreasing; the patient may be admitted with mild disease, but after 1-5 days it may deteriorate and the score may increase again. Thus, a single APACHE II score cannot fully predict prognosis but only indicates the severity of the disease at the time of scoring. While the Ranson criteria are assessed at 48 hours of admission, the APACHE II system can be used to determine the severity of acute pancreatitis at any point in time, but a single score has limited significance. It should be scored several times during the course of the disease, recorded immediately upon admission, and can be scored dynamically and continuously day by day, reflecting not only the severity of the disease but also the effectiveness of therapeutic measures, and the method can be used to compare the severity grading of information among hospitals. In recent years, with the application of growth inhibitors, the development of imaging technology, intensive care, the improvement of parenteral nutrition support and the rational use of effective antibiotics, we believe that many non-operative treatment of severe acute pancreatitis is cured after conversion to mild disease. Premature surgery when pancreatic necrosis is a sterile, hard nodular lesion with unclear mesothelial limits, surgery cannot achieve the expected effect of removing pancreatic necrotic tissue, increasing the number of operations, and the result of surgical drainage of sterile necrosis can increase the occurrence of hospital-acquired infections. This shows that: the selection of indications and timing of surgery for acute pancreatitis is extremely important. The indications and timing of surgery in the treatment of severe acute pancreatitis have been a matter of debate. In severe acute pancreatitis, the treatment opinion originally swung from non-surgical treatment to aggressive surgical treatment, and after years of experience, it shifted to non-surgical treatment or uncertainty about what treatment to implement individualized treatment. In fact, in any clinical case, any surgical or medical treatment is individualized. In the case of mild acute pancreatitis, there is a consensus that most of the cases can be cured by non-operative treatment. In case of biliary acute pancreatitis, after non-operative treatment, elective biliary surgery is better than emergency surgery; however, acute pancreatitis with acute suppurative cholangitis should be performed as an absolute immediate surgical indication for emergency surgery. In the case of large pieces of infected necrosis, surgical drainage and removal of necrotic tissue should be performed immediately, and the boundary between necrosis and normal tissue can be determined at this time. However, the occurrence of necrosis, liquefaction and infection in various parts of the pancreas in acute pancreatitis is not synchronized, and after surgical removal of infected necrotic foci, infected necrosis may occur again in other parts. Therefore, re-operation is difficult to avoid.