The invention relates to a bronchial catheter with a single cavity and double sacs, comprising a single-cavity catheter, a catheter interface, a breathing loop adapter (including a bronchofiberscope inlet, an inlet cap, a sampling tube and a breathing loop interface), a drainage tube interface, a drainage tube interface cap, a drainage tube, a trachea air sac inflation tube, a trachea air sac air valve, a trachea air sac, a bronchial air sac inflation tube, a bronchial air sac air valve, a bronchial air sac, an affected side blocking segment, a drainage tube opening, a bronchial catheter opening, a carina pothook and a single-side indicatrix. The invention has the advantages that the pipe diameter of the bronchial catheter is approach to that of a common bronchial catheter with a single cavity, the catheter is convenient to replace and is not easy to damage; a remote end arc-shaped structure has a guiding function and is convenient to locate; single or double lungs are regulated to aerate through the inflation and the deflation of the air sacs, which is simple, convenient and flexible; the double sacs are good in structure fixation, are not easy to move and have high safety; the drainage tube can assist in draining, exhausting and repeatedly expanding of the side lung of a patient and ensure the aerating effect, and the near end of the drainage tube can be sealed; and the bronchial catheter can ensure safe operation and is simple and convenient to operate.