Acute pancreatitis happens rapidly and leads to patient's condition changing swiftly.Acute pancreatitis may be complicated by acute lung injury (ALI) and acute respiratory distress syndrome (ARDS),or even multiple organ dysfunction syndrome,and the mortality rate has been high.The mechanism of acute pancreatitis with complications of ALI and ARDS is intricate.It involves the uncontrolled inflammatory response,the damage and apoptosis of cell,the role of trypsin,the imbalance of coagulation and fibrinolysis,etc.These respects interrelate with each other,forming a complex network.Further study of mechanism of acute pancreatitis complicated with ALI and ARDS will supply more new target for clinical diagnosis and treatment.