Abstract: To improve diagnostic technique on tracheal bronchus diseases. MethodsThe clinical data of 1 patient with a tracheal bronchus foreign body were retrospectively analyzed. ResultsBy screw CT gas channel and threedimensional reconstruction, the tracheal bronchus was found accompanied by a bronchus foreign body. The foreign body was taken out, and the tracheal bronchus was not processed. ConclusionThe tracheal bronchus stems from the trachea wall′s bronchial tube dystopia above the carina of the trachea or unnecessary malformation. The screw CT lung gas channel and threedimensional reconstruction may help diagnosis. It must not be used if there is not a clinical symptom.