An important measure to improve the health economics of lung cancer screening is to select the screening population appropriately and accurately and to minimize the proportion of “invalid screens”. Several large screening studies have been conducted or completed that have selected “high-risk populations,” but the definition of high-risk populations varies from study to study. U.S. Lung Cancer Screening Trial: Defined high-risk group: age 55-74 years, history of smoking ≥30 packs/year, and no more than 15 years of smoking cessation. International Early Lung Cancer Action Plan: Defined high-risk groups: age ≥ 40 years, history of smoking ≥ 10 packs/year, quit smoking no more than 15 years, or history of passive smoking, occupational exposure (asbestos, beryllium, uranium, or radon). Because of the complex etiology of lung cancer and the limited epidemiological data, it is difficult for physicians to determine the exact incidence of lung cancer in the presence of different risk factors. Therefore, it is also difficult to accurately define “high-risk groups”. In addition, adenocarcinoma is now becoming more common in a large proportion of non-smoking women, and the risk factors for the development of this disease in these patients are difficult to define and quantify, and this “high-risk group” is still not included in the screening process. Clearly, the definition of risk factors based solely on age and smoking status is not sufficient. Therefore, determining which individuals need to be screened and individualizing the frequency of screening for individuals at different risk levels is a pressing issue and a challenge for future lung cancer screening studies. The detection rate of lung cancer in international screening studies with larger samples is 1.3%-2.7%, which is much higher than the detection rate of lung cancer in the general population, and most of them are early-stage cases. The expected 10-year survival rate of lung cancer detected by screening is 80%, and if timely surgery is performed, the expected 10-year survival rate is as high as 92%. This shows that LDCT screening can significantly improve the prognosis of lung cancer.