For general routine physical examination of healthy people, ordinary chest X-ray and serum tumor marker examination can meet most of the needs. If lung cancer is suspected or proposed to be diagnosed, in order to further confirm the diagnosis and make accurate staging, the following examinations should be performed: (1) Imaging examination: (1) Chest CT: to understand the location, size, characteristics, relationship with adjacent tissues or organs, mediastinal and hilar lymph nodes of the lesion. (2) Abdominal ultrasound: to understand the abdominal important organs such as liver, kidney, adrenal gland and abdominal lymph nodes for abnormalities. If necessary, whole-body bone imaging and cranial MRI should also be performed. 2.Cellular or histological examination: If tumor is highly suspected or clinically diagnosed, further cellular or histological examination should be performed to obtain a conclusive diagnosis and to clarify the pathological type of tumor and guide the treatment. Commonly used examinations include: (1) Sputum exfoliative cytology examination: usually taken in the morning, deep tracheal sputum is required, and blood sputum is better. (2) Fiberoptic bronchoscopy: suitable for biopsy of central lung masses. (3) Percutaneous lung aspiration biopsy: usually performed under CT guidance, suitable for biopsy of peripheral type lung masses. (4) Superficial lymph node biopsy: If there are enlarged lymph nodes in the neck or axilla, lymph node aspiration or excisional biopsy can be considered. (5) Chest and abdominal fluid exfoliation cytology test: If the patient has chest or abdominal fluid, a certain amount of fluid can be extracted for cytology test. (3) Hematological examination: including biochemistry, blood routine, tumor markers, immune function, etc. The purpose is to understand the physical condition of the patient and the reserve function of important organs. All the above examinations should be reasonably arranged, following the principle of from simple to complex and from non-invasive to invasive.