Determining the type of lung cancer requires biopsy of the patient. Current biopsy methods include ultrasound and CT-guided puncture biopsy: a portion of the diseased tissue is extracted and examined. Puncture biopsy may seem painful, but it is not too uncomfortable because there will be local anesthetic. Bronchoscopy allows access to the body’s tracheobronchial tubes through the nasal cavity to see details of the lungs. Bronchoscopy is not too comfortable of a test. However, lung puncture can only take tumor tissue relatively close to the chest wall, and tracheoscopy is needed for central lung cancer and lymph nodes around the trachea. Therefore, tracheoscopy is also an indispensable method in lung cancer examination. Mediastinoscopy is an examination for patients with no enlarged lymph nodes in the supraclavicular region and enlarged lymph nodes in the mediastinum. Mediastinoscopy should be performed in the operating room under general anesthesia. The mediastinoscope is accessed through a suprasternal notch and provides access to a number of bullae and hilar lymph nodes, parabronchial and paratracheal lymph nodes, and the posterior superior mediastinum. In case of poor access to tumor tissue specimens, we can also use liquid specimens – peripheral blood for testing, which is relatively easy to do by drawing a tube of venous blood. However, the accuracy of peripheral blood test is relatively low, and it is mainly used as a basis for drug selection and treatment in special cases.