Lung cancer can be prevented and controlled. Studies have shown that the incidence and mortality rate of lung cancer in western countries have decreased significantly in recent years through tobacco control and environmental protection. The prevention of lung cancer can be divided into three levels of prevention: primary prevention is the etiological intervention; secondary prevention is the screening and early diagnosis of lung cancer to achieve early diagnosis and treatment of lung cancer; tertiary prevention is rehabilitation prevention. Primary prevention: 1. Prohibition and control of smoking Foreign studies have proved that quitting smoking can significantly reduce the incidence of lung cancer, and the sooner you quit smoking, the more significant the reduction of lung cancer incidence. Therefore, smoking cessation is the most effective way to prevent lung cancer. 2.Protection of environment It has been proved that the exposure dose of air pollution, deposition index, smoke index, benzopyrene, etc. is positively correlated with the incidence of lung cancer, so protecting the environment and reducing air pollution are important measures to reduce the incidence of lung cancer. 3.Prevention of occupational factors Many occupational carcinogens have been recognized to increase the incidence of lung cancer, and reducing the exposure to occupational carcinogens can reduce the incidence of lung cancer. 4.Scientific diet Increasing vegetables and fruits in the diet can prevent lung cancer.