In the process of bronchoscopy, after the bronchoscope clamps tumor tissues, they all run in the airway and do not pass through soft tissue structures, so they will not cause tumor cell implantation, and thus will not cause lung cancer metastasis and spread. Although bronchoscopy is an important and direct examination item for lung cancer diagnosis, it should be used with caution for the following three conditions: 1) patients with severely reduced cardiopulmonary function and extremely weak systemic condition; 2) patients with severe lung infection and acute hyperthermia, which should be performed only after anti-infection treatment or hyperthermia control; 3) patients with acute hemoptysis. Because of the thin tube of fibrinoscopy, it is not easy to suck out a large number of clots, if necessary, the examination can be performed through the oral cannula, but we should strictly control the indications and prevent asphyxia.