Objective To discuss the imaging characteristics and clinical treatment methods of congenital biliary dilation. Methods Clinical data of 70 cases of congenital biliary dilation who treated in The Third Affiliated Hospital of Henan University of TCM and Henan Provincial People’s Hospital from Jan. 2010 to Jan. 2015 was collected and analyzed. Methods Along the bile duct region (all cases received ultrasound), the ultrasound of 57 cases (81.4%) showed irregular spherical, spindle, or prismatic area without echo connected to the proximal part of the bile duct, the intracavity wall of it was skin pass rolling, and part of it had the spotty detailed or slightly strong stones sound shadow, 1 case combined spindle or capsular area without echo connected to the intrahepatic bile duct partly and along with it. CT of 45 cases (64.3%, 43 cases were diagnosed as congenital biliary dilation) without and with enhancement scanning showed low-density and irregular oblate, cystiform, columniform or fusiform expansion shadow, slight mass effect, no difference before and after the enhancement of partial intrahepatic bile duct and choledoch, and that the structure of surrounding tissues were compressed, lapsed, and deformed. The MRI and magnetic resonance cholangiopancreatography (MRCP) inspection of 65 cases (92.8%, all of 65 cases were diagnosed as congenital biliary dilation) showed tadpole-shaped, irregular cystiform, columniform or fusiform expansion with long T2 and high MRCP signal shadow image of partial intrahepatic bile duct and choledoch, the dilated bile duct also being connected to biliary tree. Of the 70 cases, there were 66 cases (94.3%) of type Ⅰ, 1 case (1.4%) of type Ⅱ, 1 case (1.4%) of type Ⅳa, 2 cases (2.9%) of type Ⅳb. Sixty eight cases (65 cases of type Ⅰ, 1 case of type Ⅱ, 2 cases of type Ⅳb) underwent cholecystectomy+dilated bile ducts resection+common hepatic duct jejunum anastomosis (Roux-en-Y), 1 case underwent cholecystectomy+dilated bile ducts resection+pancreatic duodenal resection, another 1 case underwent cholecystectomy+dilated bile ducts resection+common hepatic duct jejunum anastomosis (Roux-en-Y)+resection of left hepatic lobe. All the cases were successfully recovered without severe complications and had no dead case, but 13 cases (18.6%) suffered from minor complications, including 6 cases of short-term abdominal pain and abdominal distension, 1 case of bile leak, 2 cases of incision infection, 3 cases of pulmonary infection, and 1 case of alteration of intestinal flora. All of the 70 cases were followed-up for 6-56 months (average of 36 months). During the follow up period, 2 cases died in reason of other incidence, 4 cases suffered from simple cholangitis, 3 cases suffered from cholangitis combined with intrahepatic bile duct stone, 2 cases suffered from cholangitis combined with intrahepatic bile duct stone, slight anastomotic stoma stenosis, and mild jaundice, 2 cases suffered from cholangitis. Conclusion Congenital biliary dilation has no typical clinical feature, but it has identifiable imaging manifestation, which can provide a theoretical foundation for congenital biliary dilation in diagnosing, preoperative evaluation, and chosing operative methods. Ultrasound is the first choice, MRI and MRCP are propitious to diagnose, locate, and classfy. The treatment of congenital biliary dilation is resecting the dilated bile ducts fully and performing the common hepatic duct jejunum anastomosis.