Generally, early lung cancer has no clinical symptoms and can only be detected by X-ray physical examination. There are two types of lung cancer, central lung cancer and peripheral lung cancer, with central lung cancer showing symptoms earlier and peripheral lung cancer showing symptoms later. Common late symptoms of lung cancer are as follows: 1. cough: the most common early symptom of lung cancer, about 1/3 of patients have different degrees of cough; 2. coughing up blood: one of the common first symptoms of lung cancer. Pleura can produce irregular chest pain, chest tightness and distension, and involvement of intermural nerve can lead to sharp pain and local pressure pain, which is aggravated by breathing, coughing and position change; 4.Fever: fever caused by obstructive pneumonia in cancer tumor can be relieved by antibiotic treatment, and cancer fever caused by tissue degeneration and necrosis in later stage, which is ineffective by antibiotic treatment. Some patients occasionally have symptoms such as night sweats, palpitations, heart fever, etc.; 5. shortness of breath caused by chest tightness and bronchial stenosis: it is more common in central lung cancer, and the shortness of breath can be aggravated when enlarged lymph nodes compress bronchi, bulge, and spread by fine bronchial alveoli, and serious shortness of breath can occur when patients have large amount of pleural effusion and pericardial effusion; 6. The loss of appetite due to infection and chest pain and the consumption caused by tumor toxin can lead to emaciation, pallor and neurological weakness, which can develop into cachexia. Early lung cancer does not have any symptom, but is only discovered occasionally when going to hospital for examination. For example, lung nodules are detected by chest spiral CT examination, which is the main means of early lung cancer detection at present.