Sputum examination of tuberculosis smear is the gold standard for the diagnosis of tuberculosis. However, there are many patients with tuberculosis who have repeatedly tested negative for TB smears, which is particularly common in clinical practice and makes it difficult to diagnose tuberculosis. At this time, a preliminary judgment can be made based on the patient’s clinical symptoms and combined with the patient’s lung imaging, and a diagnosis can also be made based on tests such as fiberoptic bronchoscopy, tuberculin test, and gamma-interferon release test. Sometimes it is difficult to distinguish tuberculosis from pneumonia and lung cancer in terms of disease symptoms and imaging, so doctors need to be rich in clinical experience.