Acute pancreatitis is an inflammatory disease of the pancreas. It has a wide range of clinical presentations, from a mild self-limiting disease to a severe with prolonged hospitalization, high morbidity of complications, and high mortality. It is very important to accurately assess the severity for AP in early phase. Various severity clinical and radiological scoring systems have been used for assessing the prognosis of acute pancreatitis. The purpose of this review is to introduce advances in classification and assessment of severity in acute pancreatitis.