The diagnosis of typical pulmonary tuberculosis is not difficult. Most of them have obvious symptoms, such as fever, night sweats, weakness, wasting and cough, sputum, hemoptysis and chest pain, especially afternoon fever and night sweats, which are the most typical symptoms of tuberculosis; lesions mostly occur in the posterior part of the upper lobe and the dorsal part of the lower lobe of both lungs. X-rays mostly show patchy shadows and cavities, with positive sputum bacteria. However, most of the tuberculosis patients seen in the clinic at present do not have the above typical manifestations, have few and mild clinical symptoms, or even no obvious conscious symptoms, have atypical manifestations on chest X-ray, and have negative sputum antacid bacilli examination and culture. The three common diseases of inflammation, tuberculosis and tumor are easily confused, which makes the diagnosis and treatment difficult. Since the widespread use of fibrinoscopy in respiratory diseases, it has played a very important role in the diagnosis, differential diagnosis and treatment of lung diseases. In particular, the application in the diagnosis of lung tumors has greatly improved the diagnosis of lung tumors. Fibrinoscopy also plays an important role in the diagnosis of pulmonary tuberculosis. The methods of fibrinoscopy, which are the same as those used in other diseases, include observation of lesions under direct vision of fibrinoscopy, lesion biopsy, brush examination, transbronchial lung biopsy, and bronchial perfusion fluid examination, which greatly improve the diagnostic ability of pulmonary tuberculosis. Fibrinoscopy should have been performed in the following cases: intrapulmonary lesions not yet diagnosed but tuberculosis cannot be excluded; pulmonary atelectasis due to unexplained bronchial obstruction; irritating dry cough; unexplained hemoptysis; suspected bronchial fistula or endobronchial tuberculosis occurring. Fibrinogenic examination should not be performed when there is: severe respiratory failure; recent myocardial infarction; severe hypertension; cardiac insufficiency and severe arrhythmias; severe pulmonary infection is found; clear bleeding tendency with impaired coagulation mechanism; and hemoptysis within one week.