To rule out lung cancer, it is necessary to go to the hospital to improve lung CT, serum tumor markers and other tests, and combine them with the patient’s symptoms to make a judgment, but you cannot make a judgment on your own. 1. Lung CT: low-dose lung CT scan can be used for initial screening. Most of the early lung cancers can be detected by chest CT, and if the result shows that there is no lesion, it can be basically ruled out. If the result shows no lesions, lung cancer can basically be excluded. If the result suggests the presence of lung nodules, attention should be paid. Further bronchoscopy or percutaneous lung lesion biopsy may be needed to confirm or exclude lung cancer. 2. Serum tumor marker test: if there is lung locoregional lesion, blood test can be performed to detect serum lung cancer markers, such as carcinoembryonic antigen, cytokeratin 19 fragment, and neurospecific enolase. 3. Lung cancer patients do not have specific symptoms, but some of them may have irritating dry cough in the early stage, and coughing sputum, hemoptysis, chest pain, shortness of breath, fever and other symptoms with the development of the disease. If the above symptoms occur, patients should consult the doctor in time to complete the above tests to rule out or confirm the diagnosis of lung cancer, and once diagnosed, patients should be treated actively to avoid delaying the condition.