I. Specific steps 1. Routine bronchoscopy. 2.Place the catheter. 3.Open the electrode arm. 4.The RF generator is activated. 5.Reset the electrode arm. 6.Arrive at another treatment site and activate again. 7.Continuous operation in all the accessible bronchi to treat the whole bronchial tree (>3mm). Recommended treatment parameters 1.Local treatment temperature is controlled at 55℃～65°C. 2.Maintenance time for each treatment site is 10s. 3.The whole treatment time is controlled at about 60 minutes.