The opportunity of and indications for operation in patients with acute necrotizing pancreatitis (ANP) are still controversial. One hundred and ninty surgical cases of ANP were analyzed. Early operation was performed in 2 weeks from onset, and late operation after 2 weeks. In the early operation, the pancreatic sporadic focal necrosis was found in most cases (75.6%), and main postoperative complications were disturbance of blood circulation and organic function injury of pancreas. The postoperative mortality rate was 28.2%. In the late operation, extensive fusional pancreatic necrosis was found in most cases (53.7), and most complications were located in the organs mear the pancreas. The authors conclude that late operation is better for the treatment of ANP. The indications of early and late operation were discussed.