The utility model discloses an invisible drainage cannula applied to a cystostomy postoperative patient and belongs to the technical field of medical instruments. The invisible drainage cannula comprises an outer cannula, a head of the outer cannula is in a mushroom-shaped structure, the head end of the outer cannula is sealed, a vertically adjustable ear-shaped fixing ring is arranged on the outer wall of the outer cannula, an inner cannula is arranged in the outer cannula in a matching mode, a seal ring is disposed between the head of the inner cannula and the outer cannula, a seal cap stopper is disposed at the tail ends of the inner cannula and the outer cannula in the matching mode, and the seal cap stopper seals the tail ends of the inner cannula and the outer cannula. By means of the cystostomy postoperative invisible drainage cannula, defects of traditional drainage catheters are overcome, the living quality of the patient is improved, the level of mental health of the patient is improved, and the patient is benefited.