Acute severe pancreatitis is a very serious disease in clinical practice, with a high mortality rate, often requiring comprehensive treatment in the ICU. Acute severe pancreatitis is a disease caused by multiple etiologies that results in localized inflammation, necrosis, and infection of the pancreas, accompanied by a systemic inflammatory response and persistent organ failure. It is divided into three phases. The first phase is the acute response phase, occurring from onset to about two weeks, characterized by systemic inflammatory response; the second phase is the systemic infection phase, occurring from two weeks to about two months, characterized by necrosis and infection of the pancreas or peripancreatic tissues; the third phase is the residual infection phase, occurring two to three months later, with clinical manifestations primarily of systemic malnutrition and persistent fistulas, accompanied by gastrointestinal fistulas.