Pancreatic cysts can be divided into pancreatic pseudocysts and true cysts. Among them, pseudocysts are following pancreatic trauma and inflammation, such as blood, exudate or pancreatic fluid spillage without infection and purulence, and the surrounding tissue fibers proliferate over time and enclose the body fluid in cysts. These cysts are not grown from the pancreas and the cyst wall is not covered by epithelial cells, so they are called pseudocysts. True cysts occur from pancreatic tissue, at least when the cyst is initially inside the pancreas, and the cyst wall is lined with pancreatic epithelial cells. They are also classified as congenital cysts, stagnant cysts, degenerative cysts, redundant cysts and parasitic cysts. In middle-aged patients with previous history of acute pancreatitis or upper abdominal trauma, the possibility of pancreatic cyst should be considered when a spherical cystic mass gradually appears later. The diagnosis of pancreatic cyst can be confirmed when the laboratory results reveal some abnormalities in the function of the pancreas, especially if the X-ray examination reveals the gastroduodenum, transverse colon and other dependent conditions, which are consistent with the cyst growing from the small omental sac. If the cyst is punctured and the fluid is examined, the diagnosis of pancreatic cyst cannot be confirmed unless a high concentration of pancreatic enzymes is found. This condition also needs to be differentiated from mesenteric cysts, hydronephrosis, polycystic kidneys, hepatic cysts, and other tumors of the retroperitoneum.