Lung cancer is a malignant tumor originating from the epithelial cells of the bronchial mucosa and ranks first among all cancers in terms of morbidity and mortality. The causes and pathogenesis of lung cancer are not yet clear, but there is evidence that it is related to various causes such as smoking and environmental pollution. Smoking is the most common cause of lung cancer, and both active and passive smoking may cause lung cancer. The risk of lung cancer is on average 10 times higher in smokers compared to never smokers. Occupational carcinogenic factors, there are many carcinogenic substances in the working environment of certain occupations, and long-term exposure will lead to an increased risk of lung cancer, such as the presence of ionizing radiation in the working environment, and engaging in radioactive ore mining and manufacturing. Genetic factors, the correlation between genetic factors and lung cancer has been emphasized. The risk of lung cancer is increased if a relative has a lung cancer patient. Air pollution, air pollution is also an important factor in causing cancer, including outdoor environmental pollution such as automobile exhaust and asphalt on roads; indoor environmental pollution such as fumes from hoods and decorative materials for decoration; people with previous chronic lung infections also have an increased risk of lung cancer, such as tuberculosis, bronchiectasis, chronic obstructive pulmonary disease, etc.; diet and nutrition have a certain relationship, such as deficiencies in vitamin A, carotene, etc. suggest an elevated risk of lung cancer.