The pancreas is an important digestive organ, and diseases of the pancreas such as pancreatitis and pancreatic cancer are very harmful to people’s health, especially pancreatic cancer, which is known as the “king of cancers” and often has a survival period of less than one year after the onset of symptoms. Because of the hidden location of the pancreas in the body – behind the peritoneum – conventional ultrasound examination is easily affected by gas and contents of the stomach and intestines, and it is difficult to see the pancreas clearly. Ultrasound endoscopy can observe the pancreas in the closest part of the body cavity – the stomach and duodenum – at close range and at will, and its diagnostic ability for pancreatic cancer is slightly higher than that of high-resolution enhanced CT, while that for pancreatic duct and common bile duct stones is significantly higher than that of CT and MRI. Most importantly, ultrasound endoscopy can perform puncture biopsy and obtain pathological diagnosis. Ultrasound endoscopy can also be used for the treatment of pancreatic diseases, such as puncture and drainage of pancreatic pseudocysts after severe pancreatitis, analgesic treatment of advanced pancreatic cancer, and local injection and placement of radioactive particles for advanced pancreatic cancer. Ultrasound endoscopic treatment of pancreatic cancer can significantly improve patients’ quality of life and prolong survival to some extent. Ultrasound endoscopic diagnosis and treatment is one of the most rapidly developing areas of minimally invasive gastrointestinal endoscopic techniques in recent years.