Acute pancreatitis (AP) is an inflammatory disorder of the pancreas. Because the mechanism is not yet fully elucidated, there is clinically no effective treatment for the severe AP. Calcium overload, premature trypsinogen activation, endoplasmic reticulum stress, autophagy, mitochondrial dysfunction and inflammatory response are considered to be closely associated with the injury of pancreatic acinar cells. Here, the authors address the research progress in this field.