The invention provides an angiocarpy sacculus dilating catheter, belonging to the angiocarpy sacculus dilating catheter. The dilating catheter comprises a lumen connector, a Y-shaped connector, a protective sleeve, an injection port, a canal, a mark ring and a sacculus, wherein one end of the Y-shaped connector is connected with the lumen connector, another end of the Y-shaped connector is provided with the injection port, and the third end of the Y-shaped connector is connected with the canal and is provided with the protective sleeve; and the front end of the canal is provided with the sacculus. The angiocarpy sacculus dilating catheter has the advantages that the sacculus dilating catheter is made of Nylon 12 and PEBAX with good biocompatibility and high pressure resistance, has good adaptability, large bursting pressure, unique structure and high safety, can be applied to interventional therapy on congenital stenosis of pulmonary valve, aortic stenosis and other diseases, and adopts single lumen sleeved sacculus structure to lead smoothness of injection and pumpback; the connection of the sacculus and the canal adopts welding process, the sacculus and the canal are integrated to greatly reduce the risk of pressuring breaking; and the thread lumen and the injection lumen are respectively arranged to reduce the risk of liquid leakage.