The invention discloses an infusion tube mouth which comprises a main tube, a movable sealing tube and a sealing outer tube. The main tube is sequentially and internally provided with a liquid inlet cavity, a sealing cavity and a limiting cavity. The diameter of the liquid inlet cavity and the diameter of the limiting cavity are both larger than the diameter of the sealing cavity. The top of the movable sealing tube is sealed, and a sealing part is arranged on the side, close to the top end, of the movable sealing tube. The diameter of the sealing part is matched with the diameter of the sealing cavity. The movable sealing tube is arranged in the main tube in a penetrating mode. A liquid inlet is formed in the side wall of the sealing part. The movable sealing tube makes the liquid inlet exposed or closed through movement. The sealing outer tube is attached to the bottom end face of the main tube so that the lower port of the main tube can be closed. By means of the infusion tube mouth, an infusion channel can be sealed when an infusion resin needle is pulled out, so the defect that liquid medicine leaks out of an infusion container or pollution is caused by butyl rubber plug cast produced by piercing is avoided, and product quality is improved.