1, obstruction: can be divided into complete obstruction and incomplete obstruction, manifested as truncated, funnel type or through (refers to pseudo-obstruction, that is, the lumen is obstructed due to tumor or inflammatory mucosal abscess when viewed by the naked eye, and can pass when biopsy forceps or cell brush is inserted downward fashion). 2.Stenosis: can be circumferential, eccentric, irregular stenosis. 3, external pressure bulge: due to extra-tubular compression, the localized tracheal or bronchial mucosa bulges out into the lumen, with smooth mucosal surface and parabolic projection. If the lymph nodes under the bulge are enlarged, the bulge is widened and fixed by compression of the bulge. Widening, deformation and distortion of the bronchial crest may also occur. 4.Dilatation: The lumen is larger than normal, the surrounding mucosal atrophy cartilage ring is clearly visible, the ridge between the orifices is thinner and sharper, and the multi-level bronchi below can be seen. 5.Displacement: trachea or bronchus is bent and displaced. 6.Secretion: plasma, mucus, purulent and blood.