After a lung mass is found and lung cancer is suspected or has been diagnosed, patients are most concerned about what stage the disease has progressed to and whether there is a chance for surgery. The treatment of lung cancer depends on accurate staging. For example, stage IA non-small cell lung cancer can be treated by surgery alone; stage IB patients with high-risk factors such as invasion of lung membranes and vascular infiltration need adjuvant chemotherapy, while those without high-risk factors can be treated by surgery alone; those with stage IIA or above need post-operative chemotherapy; those without distant metastasis or contralateral lymph node metastasis before treatment, but with metastasis in ipsilateral mediastinal lymph nodes need pre-operative chemotherapy or pre-operative radiotherapy If there is no distant metastasis before treatment, but there is metastasis in the ipsilateral mediastinal lymph nodes, preoperative chemotherapy or preoperative radiotherapy is required. Those with distant metastases or contralateral lymph node metastases can only be treated with palliative chemotherapy or targeted therapy. Thus, staging is crucial before treatment, and assessment of mediastinal lymph node metastasis is the most important part of staging before treatment for resectable lung cancer. At present, lung cancer staging methods include non-invasive staging and invasive staging. Non-invasive staging methods include ultrasound, CT, MRI, ECT, PET/CT; invasive staging methods include ultrasound bronchoscopic puncture biopsy (EBUS), mediastinoscopy, television-assisted mediastinoscopic mediastinal lymph node dissection (VAMLA), flexible thoracoscopy, surgical thoracoscopic exploratory biopsy, etc. The main tools used to assess the status of mediastinal lymph nodes are CT, PET/CT, EBUS, mediastinoscopy and VAMLA, the accuracy of which increases in descending order, i.e. CT is the worst and VAMLA is the best. Since VAMLA can remove bilateral upper mediastinal lymph nodes, which is more extensive than conventional radical lung cancer surgery, overseas studies have shown that VAMLA not only can obtain accurate staging but also can improve survival rate.