Recently, many families brought their babies to our hospital and found that the babies had yellow skin, sometimes fever, and white stools, and were found to have “congenital common bile duct cyst”, also known as common bile duct dilatation. The cause of congenital common bile duct cysts is unknown, and most scholars believe that the disease is associated with congenital abnormal biliopancreatic duct coaptation, distal obstruction of the common bile duct, and biliary dysplasia, viral infection, or abnormal nerve distribution. Congenital common bile duct cyst has 3 basic symptoms: jaundice, abdominal pain, and mass, but not all patients have all 3 main symptoms in their medical history or at the time of consultation, and often only 1, 2, or 3 symptoms are present clinically. 1, abdominal pain: recurrent right upper abdomen or middle epigastric pain, the nature and degree vary, sometimes colic pulling pain or slight distension; secondary infection may be accompanied by fever; sometimes there is nausea; with abdominal pain accounted for about 80% to 90%. 2, the mass: located in the right upper abdomen under the rib cage, the upper boundary is covered by the liver edge, huge can go beyond the abdominal midline, the cystic sense of small choledochal cysts because of the deep location is not easy to find, in the infection pain jaundice attack when the mass increases, after the improvement and can shrink, and so on repeatedly. The right upper abdominal swelling accounted for about 70% of those who visited the clinic 3, jaundice: about 50% of cases have jaundice. The degree of jaundice is directly related to the degree of biliary obstruction. Jaundice is usually recurrent, mostly combined with infection and fever. Most of the above symptoms are intermittent episodes, due to the distal exit of the common bile duct is not open to the contents of the retention, the emergence of biliary tract infection so that the symptoms of the attack, after treatment for a few days after the smooth drainage of the contents of the symptoms reduced or disappeared, some children have frequent attacks, some can be once every few months. In addition to the above symptoms, the attack may be accompanied by nausea and vomiting, and jaundice may occur with white clay-like stools and deepened urine color. In individual children, especially infants, cyst perforation can cause acute cholestatic peritonitis with high fever and abdominal distension and even shock. The initial clinical diagnosis is based on the clinical manifestations of the three main symptoms of abdominal pain, jaundice and cystic mass in the right upper abdomen, and some cases do not have the “three main symptoms” and laboratory and ancillary tests should be performed to help confirm the diagnosis. The initial examination of congenital choledochal cyst can be made by ultrasound, CT and imaging, etc. Ultrasound is the easiest and non-invasive examination tool to obtain the initial diagnosis. There are many complications of congenital common bile duct cyst: cholestasis, portal hypertension, cholangitis, pancreatitis, stone formation in the cystic cavity, bleeding, cyst perforation or rupture, cyst cancer, etc. It is recommended to perform ultrasound examination for babies found with the above clinical manifestations, expecting early detection and early treatment to reduce the occurrence of complications. Without early surgical treatment, this disease can lead to death due to recurrent infections, biliary cirrhosis, perforation of the common bile duct or carcinoma. Therefore, when a child is found to have yellow skin, the disease should be thought of, and surgery should be performed promptly after affirmation of the diagnosis. At present, the common surgical methods are: cystectomy, Roux-Y anastomosis of common hepatic duct jejunum with anti-reflux valvuloplasty. Yangzhou Maternal and Child Health Hospital has rich experience in the treatment of this disease.