The time of urinary amylase elevation in acute pancreatitis review starts to rise only 24 hours after the onset of acute pancreatitis, and reaches the maximum peak of urinary amylase in 1-2 days, then slowly declines, and can basically return to normal after about 2 weeks. In some acute severe hemorrhagic necrotizing pancreatitis, the value of urinary amylase may rise, fall and rise again repeatedly. The urinary amylase cannot simply evaluate the severity of acute pancreatitis, but should also be combined with serum amylase and blood lipase, and the specific assessment and comparison of acute pancreatitis from imaging, review CT or enhanced CT of the pancreas, and then combined with the enzymatic performance of blood and urinary amylase, can effectively assess the severity of acute pancreatitis.