Benign airway stenosis caused by scarring and granulomas is not uncommon clinically. The common causes of scar stenosis include airway stenosis with occlusive tuberculosis, scar stenosis after tracheal intubation or incision, and scar stenosis after cauterization of intra-airway tumors, etc. The common causes of granuloma formation in the airway include granuloma formed after endoprosthesis, airway proliferative tuberculosis, foreign body granuloma, nodular disease granuloma, inflammatory granuloma, and post-burn granuloma. In the past, surgical resection of the narrowed airway was the main treatment, but it is difficult to carry out this procedure widely in the clinic because of the high trauma, high technical requirements, and many postoperative complications. In recent years, with the development of endoscopic technology, bronchoscopic intervention is one of the most effective methods for benign airway stenosis, such as endostent placement or argon plasma coagulation (APC). Using bronchoscopy and two or more interventional techniques (including laser, high-frequency electric knife, argon knife, cryopreservation, balloon dilation, stent placement, etc.), etc., the majority of patients can be cured. The authors used a combination of APC and cryo in recent years to treat 44 lesions in 34 cases of benign airway stenosis, and the first treatment was performed by inserting a rigid mirror combined with a soft mirror under general anesthesia in 12 patients and a soft mirror under local anesthesia in 32 patients. RESULTS: The airway stenosis before treatment was close to 2/3 in both the scar and sarcoid groups, with significant shortness of breath. After argon knife combined with cryotherapy, the degree of stenosis was significantly reduced in both groups, and the symptoms of shortness of breath were relieved, indicating that APC combined with cryotherapy had significant efficacy on both scar and granuloma in the airway, and the treatment effects were similar. The combined treatment effect resulted in a cure rate of 81.8% within six months. Argon gas knife (APC) is a new type of high-frequency electric knife, which delivers high-frequency current to the target tissue through ionized argon gas, avoiding direct contact between electrodes and tissue, and is a non-contact high-frequency electrocoagulation technique. aPC has the effect of rapidly ablating intra-airway scar and granuloma tissue, and the first ablation range can reach about 70%, and the quality of life of patients is significantly improved, especially for patients with tracheal lesions The improvement is particularly significant in patients with tracheal lesions, and has resulted in the unblocking of the airway in many patients who were on the verge of asphyxia. In the case of scar stenosis, early enlargement of the lumen with argon knife and prevention of recurrence of the stenosis with cryopreservation is advisable, followed by continued treatment of the regenerating granuloma with cryopreservation. Generally, the scar formation is more active within 3 months, and if not treated promptly, the stenosis will remain within 2 weeks. If treatment with cryotherapy is maintained for 3 months thereafter, 61.5% will be cured. If an internal stent (either a permeable stent or a bare metal stent) is placed within 1 month, granulomas may form at both ends of the permeable stent or from the mesh of the bare stent 2 to 30 days after stent placement. Once granuloma is formed, do not simply perform thermal ablation such as laser, microwave or APC, but combine it with cryotherapy and remove the stent in time, and treat the residual granuloma with argon knife and cryotherapy, and do not place stents on top of each other. Treatment of granuloma in the airway: If the granuloma has a clear cause, the granuloma formation will stop in some patients after the cause is removed. For granulomas that form after endoprosthesis placement, the endoprosthesis must be removed promptly. Cryopreservation has a significant inhibitory effect on the control of scar and granuloma formation in the late stage of treatment. For foreign body granuloma after removing the foreign body, APC combined with cryotherapy of granulation tissue, the granulation disappears after two more subsequent treatments, and the canal wall is shaped normally after 1 month. For proliferative airway tuberculosis, APC combined with freezing and submucosal anti-tuberculosis drug injection resulted in stable disease after 3-6 months. The cause of benign airway stenosis in this group was airway tuberculosis in the first place (52.9%), which may be related to the high incidence of pulmonary tuberculosis in China and the delay in treatment due to the failure to diagnose the disease in its early stage, and should be highly valued by clinicians. In severe cases of airway narrowing caused by tuberculosis granuloma, APC or cryotherapy is used first to enlarge the lumen and, if necessary, to dilate the balloon airway. Balloon dilation is also a good treatment for airway stenosis, but it is still prone to recurrence after surgery and requires re-expansion every 1 to 2 months, causing great pain to patients. In our group, there were 5 cases in which only balloon dilation was performed and then cryopreservation was given, and then the condition was stabilized after 3 consecutive cryopreservation treatments. Nowadays, most hospitals still adopt stenting or balloon dilation treatment alone, which is inappropriate, especially for bare metal stents, and it is difficult to deal with granuloma and airway stenosis formed again, and the stent is not easy to remove. It should be emphasized that the distal bronchus in the stenosis area must be kept open, and if the distal bronchus is occluded, there is no need for interventional treatment. In our two cases of complete pulmonary atelectasis, APC combined with cryopreservation failed to clear. Also, endoluminal intervention must be combined with an adequate course of antituberculosis therapy or bronchoscopic injection of antituberculosis drugs, and in general, stents should not be placed, as this will stimulate local granulation tissue proliferation. The rigid mirror keeps the airway open and has a lateral hole at the operating end connected to the ventilator, so it is also called a “ventilating bronchoscope”. The modern value of the rigid microscope is that it is a major tool in modern interventional pulmonology as an interventional channel that allows soft bronchoscopes and other instruments to enter the airway, greatly broadening its scope of application, allowing stent release, laser ablation, argon plasma coagulation (APC), foreign body extraction and freezing under direct vision. The 12 patients in this group were operated under rigid microscopy, mainly for patients with severe stenosis of the main airway, which, combined with soft microscopy, can unblock the airway more quickly and ensure patient safety. Clinically, benign airway stenosis is much less than malignant airway stenosis. At present, there is no standardized treatment plan at home and abroad, and some units have a single treatment method, which can only choose thermal ablation (laser or microwave, APC) or placement of endotracheal stents, which are very easy to recur after surgery, making benign lesions become “persistent” or causing serious adverse consequences. After clinical practice in recent years, the authors’ experience in the treatment of benign airway stenosis is as follows: 1. Whether it is scarred airway stenosis or granulomatous airway stenosis, APC combined with freezing can significantly reduce the obstructive symptoms and improve the patient’s quality of life; however, single treatment is prone to recurrence; 2. If necessary, balloon catheter dilation can be used first, then combined with cryotherapy. It is still easy to recur after balloon dilation alone. Do not rush the application of APC or stents, especially the application of bare metal stents is prohibited. If necessary, a retrievable stent should be placed and removed after 3 to 6 months. Once granuloma is formed after stent placement, the stent should be removed promptly and stents should not be placed on top of each other; 3. For severe scarring airway stenosis, APC combined with cryotherapy should be preferred, and thereafter, cryotherapy should be the main treatment, which can be done once a week at the beginning and gradually extend the treatment interval for 3 to 6 months continuously; 4. removed, and at the same time combined with freezing to treat the residual site, thereafter, freezing treatment should be the main treatment until the disease develops; 5. For tuberculous or inflammatory granuloma, the granuloma can be removed with APC first, and then combined with freezing and local anti-tuberculous drug (tuberculous granuloma) injection, and stent placement is generally not advisable.