In the diagnosis and treatment of lung cancer, obtaining a pathologic diagnosis is crucial. It is often necessary to perform invasive examinations such as lung puncture biopsy, closed chest drainage, tracheoscopy, thoracoscopy and mediastinoscopy to obtain case specimens. What are the characteristics of these examinations, what are the advantages and shortcomings, and how to utilize these examinations are now elaborated one by one. 1. Lung puncture biopsy: It is a method of using a puncture needle to enter the lungs through the skin, chest wall and pleura to obtain tissues, and is generally used for the diagnosis of peripheral lung nodules or lung masses. The shortest path is usually chosen for localization and requires guidance in ultrasound or CT localization. The puncture needle follows the path of the ultrasound or CT localization into the lung to reach the nodule or mass site. The most common complication is pneumothorax, the incidence is about 6%-35%, bleeding: the incidence is about 3%-30%. 2.Closed thoracic drainage: Closed thoracic drainage refers to the insertion of drainage tubes into the thoracic cavity, which are placed underneath closed water-sealed bottles to drain the gas or liquid from the pleural cavity outside the body, and has been a method of re-establishing negative pressure in the pleural cavity. As a treatment means widely used in hemothorax, pneumothorax, pyothorax drainage and open thoracotomy, also used for the diagnosis and treatment of patients with pleural effusion, pleural fluid sent to the examination several times can assist in the diagnosis. 3.Electronic bronchoscopy (EOB): It is the main method to diagnose central lung cancer, and can perform direct biopsy and scraping of lesions with high positive rate. Bronchoscopic feasible lung biopsy (TBLB), alveolar lavage and brushing test also have certain diagnostic rate for peripheral lung cancer. The main indications for bronchoscopy are patients with suspected lung cancer who have centralized lesions (including masses, nodules, recurrent infiltrative lesions in the lungs or infiltrative shadows that do not subside) found on chest CT, negative sputum exfoliative cytology, or positive sputum cytology and negative chest imaging. Bronchoscopy is mainly used for screening and early diagnosis of early central lung cancer, and cytology and histology specimens can be obtained. For peripheral lung cancer, cytology or histology specimens can be obtained by bronchoalveolar lavage or transbronchial needle aspiration biopsy. 4.Transbronchial needle aspiration biopsy (TBNA): TBNA can be performed through bronchoscopy on mediastinal and hilar lymph nodes or masses, which is conducive to the diagnosis and staging of lung cancer; TBNA does not show the tissues around the masses clearly, and is prone to be mistakenly penetrated. 5.Ultrasonic bronchoscopy (E-BUS): It is to combine the miniature ultrasound probe with common fiberoptic bronchoscope to perform real-time ultrasound scanning examination in the lumen of tracheobronchial tubes, in order to understand the ultrasound characteristics of tissues of tracheobronchial tubular wall and the surrounding neighboring organs, so as to improve the diagnostic level. The examination is applied in combination with fine-needle puncture, which can clearly see the position of the occupying lesions in the lungs and the surrounding blood vessels and lymph nodes, which completely solves the problem of blind puncture of traditional bronchoscopy, effectively avoids blood vessel damage during puncture, reduces the possibility of hemorrhage of the patient, and improves the safety and accuracy of bronchial biopsy. 6.Fluorescence bronchoscopy (LIFE): some tissue cells can emit fluorescence under the irradiation of certain wavelengths of light, and the fluorescence color emitted by cancerous tissues is different from that of normal tissues, which can differentiate the two. Fluorescence fiberoptic bronchoscopy is a product of the combination of high-resolution camera, computer, fiberoptic bronchoscope and other technologies, which can detect pre-cancerous lesions such as carcinoma in situ and atypical hyperplasia of bronchial mucosa for biopsy of the lesion site, which is conducive to the discovery of multiple foci of carcinoma in situ and the extent of infiltration of lung cancer, so as to better select the scope of surgical resection. The accuracy of diagnosis of atypical hyperplasia cells, carcinoma in situ and infiltrative lung cancer is also higher than that of ordinary bronchoscopy. It helps to improve the level of early diagnosis and early treatment of lung cancer. 7.Electromagnetic navigation bronchoscope: Due to the limitation of diameter, ordinary bronchoscope can only reach the 2nd level lobe bronchus under direct vision, and it is often used in the diagnosis and treatment of centralized lesions. Although fine bronchoscopy combined with small ultrasound probe can break through the technical bottleneck to enter the 5th, 6th and even farther fine bronchus, but to find the most suitable access to the lesion has been a time-consuming and laborious project. Electromagnetic navigation bronchoscopy is a new technology that combines electromagnetic navigation technology with bronchoscopy and three-dimensional reconstruction technology, utilizing an extracorporeal magnetic field positioning plate to guide the airway probe to the target lesion. It enters the lungs through the natural cavities of the human body and accurately locates the lesions deep in the lungs, with the advantages of ultra-minimally invasive, highly accurate and fast and effective. It is a new minimally invasive diagnostic and therapeutic equipment, which can be used for the diagnosis and treatment of peripheral-type lesions, and seldom pneumothorax occurs. 8.Thoracoscopy: When thoracocentesis and pleural biopsy cannot clarify the etiology of pleural diseases, it may be helpful to perform a pleural biopsy of the dirty layer or the wall layer under the direct vision of thoracoscopy before performing an open thoracic biopsy. Thoracoscopy can also be used to inject talcum powder, other sclerosing agents, or chemotherapeutic agents directly or dispersed into the pleural cavity for the treatment of patients with malignant pleural effusions, and approximately one-half of those who cannot be diagnosed definitively by cytology and pleural biopsy are definitively diagnosed by thoracoscopy. Thoracoscopy has the advantages of simple operation, less invasive, and can be carried out under local anesthesia. Mediastinoscopy: It can be used for staging of lung cancer, especially for patients with enlarged mediastinal lymph nodes on enhanced CT scan. Conventional diagnosis of mediastinal lymph node metastasis of lung cancer has been gradually replaced by less invasive ultrasonic tracheoscopy. Mediastinoscopy is more commonly used to diagnose mediastinal masses or to perform lymph node sampling in patients with lymphoma or granulomatous lesions. Mediastinoscopy should be performed under general anesthesia in the operating room. Mediastinoscopy is accessed through a suprasternal notch incision, which allows access to some hilum and hilar lymph nodes, parabronchial and paratracheal lymph nodes, and the posterior superior mediastinum. Complication rates are <1% and include bleeding, vocal cord paralysis due to injury to the laryngeal reentrant nerve, and celiac disease due to injury to the thoracic duct. The use of these invasive tests can meet the diagnostic needs of the vast majority of lung cancer patients. How to choose/use these invasive examination techniques needs to be decided according to the characteristics of the lesion, the general condition of the patient, the economic situation and other comprehensive analysis, so as to choose an optimal examination and diagnosis method for the patient.