Abstract: Presently, tremendous progress has been achieved in the research of acute pancreatitis (AP), which lead to significant changes in many important aspects of the diagnosis and treatment for AP. In 2014, the Pancreatic Surgery Group of Surgery Branch of Chinese Medical Association revised the Guidelines for the Diagnosis and Treatment of Severe Acute Pancreatitis which was published in 2007. In the revised guidelines, the severity of AP is classified as mild acute pancreatitis (MAP), moderately severe acutepancreatitis (MSAP) and severe acute pancreatitis (SAP). The definition of SAP or MSAP depends on the duration of organ failure, which is persistent (>48 hours) in SAP but is transient (≤48 hours) in MSAP. Modified CT severity index (MCTSI) is used as the imaging evaluation. Acute peri pancreatic fluid collection (APFC), acute necrotic collection (ANC), walledoff necrosis (WON) and pancreatic pseudocyst are the local complications. The disease course is divided into 3 stages, including early stage (acute phase), middle stage (evolution phase) and late stage (infection phase). Infected necrosis is an indication for the surgical treatment, but the surgery should not be performed in sterile necrosis. Meanwhile, surgical treatment should follow the delayed principle. Surgical methods that include percutaneous drainage (PCD), minimally invasive surgery and open surgery could be selected separately or jointly.