The prevention of lung cancer is divided into three levels of prevention: 1. Primary prevention mainly focuses on the cause of the disease, mainly controlling smoking, improving the environment, developing labor hygiene, and reducing the incidence of professional lung cancer. Through dietary prevention and patient prevention. Keeping away from tobacco plays an important role in the prevention and treatment of lung cancer. After long-term smoking, the seeds of tumor have long been rooted and sprouted on the soil, and the solution is to quit smoking as early as possible to improve the soil where the seeds grow. The results of a large number of studies at home and abroad suggest that lung cancer patients should receive smoking cessation treatment. Relevant research suggests that the 5-year survival rate of 65-year-old early lung cancer patients who continue to smoke and those who quit smoking are 33% and 70% respectively, while the 5-year survival rate of patients with limited-stage small-cell lung cancer is 29% and 63% respectively. Obviously, it is never too late to quit smoking, and even if you already have lung cancer, quitting smoking can still have a significant impact on your prognosis. The results of a large number of epidemiological studies show that smoking cessation can lead to a decrease in the incidence of lung cancer. A study in the British Medical Journal pointed out that the “cumulative risk” of lung cancer death for men who quit smoking before the age of 75 is 16%, while the “cumulative risk” of quitting smoking before the age of 30 is less than 2%, and the risk of lung cancer can be reduced even if a man quits smoking in his middle age. Even if people quit smoking in middle age, it can also reduce the risk of lung cancer, so it can be seen that the earlier you quit smoking, the better. In recent years, with the implementation of laws and regulations restricting smoking in some European and American countries such as the United States, the United Kingdom and the Netherlands, the mortality rate of lung cancer among men has stabilized or decreased. In the United States, the smoking rate of the male population has been significantly reduced in the past 30 years, as a result, the incidence of lung cancer in recent years has shown a downward trend, but on the contrary, the incidence of lung cancer in females has risen, which is obviously related to the increase of smoking rate in the female population in recent years. According to a follow-up survey on smoking cessation, the incidence of lung cancer showed a gradual decline after smoking cessation. Within 1-3 years of quitting smoking, the incidence of lung cancer decreases by about 1/10; after 6 years of quitting smoking, the incidence of lung cancer decreases by more than half; after 15 years of quitting smoking, the incidence of lung cancer is similar to that of non-smokers. Heavy smokers (more than 15 cigarettes per day) have a significantly lower risk of lung cancer after reducing their smoking by half, and the mortality rate of lung cancer decreases after stopping smoking; after 10 years of quitting smoking, the incidence of lung cancer decreases to roughly the same rate as that of nonsmokers. The incidence of lung cancer after 10 years of smoking cessation is roughly the same as that of non-smokers. Stopping smoking may prolong survival and reduce the recurrence rate of lung cancer. Since the lung cancer suffered by non-smokers has some brand new pathological characteristics, they are more effective in responding to some therapies, especially some targeted therapeutic drugs that have emerged in recent years. Secondary prevention mainly focuses on early detection, early diagnosis and early treatment through lung cancer screening. 3. Tertiary prevention focuses on clinical treatment. It is to get a better effect and reduce the chance of recurrence and metastasis through comprehensive treatment after illness. Through rehabilitation, palliative and pain-relieving treatments, psychotherapy, nutrition and exercise support, the long-term survival rate of patients can be improved as much as possible to enhance the quality of life. Although lung cancer is scary, it is preventable and treatable. Experts suggest that tumors can be effectively prevented by changing bad lifestyle, tumors can be detected early through health checkups and screening programs, tumors can be better cured through standardized diagnostic and therapeutic behaviors, and patients’ quality of life can be ensured to the maximum extent through existing diagnostic and therapeutic means while improving the effect of tumor treatment. With the extensive development of targeted therapy and comprehensive treatment, lung cancer is also developing in the direction of chronic disease. In the future, the treatment of lung cancer will also control the development of the disease through various means as other benign diseases.