The means of confirming the diagnosis of lung cancer mainly include: 1) clinical manifestations: clinical manifestations, such as the presence or absence of cough, sputum, chest pain, enlarged lymph nodes and other important factors; 2) imaging features: if clinical manifestations are present, it is necessary to combine with the imaging features, such as magnetic resonance, CT, PET-CT, DR, etc.; 3) pathological biopsy: through fiberoptic bronchoscopy to take a biopsy or by percutaneous puncture to take out the mass tissue of the lung for biopsy; exfoliated cells from chest water and CTC circulating tumor cytology are also important means of detecting lung cancer. Biopsy; taking exfoliated cells from pleural fluid and CTC circulating tumor cell examination are also important ways to detect lung cancer. Pathologic biopsy is the gold standard for lung cancer diagnosis.