Not most people have lung nodules, only some people have lung nodules. Lung nodules are common clinical signs in imaging, but not most people have them. Lung nodules are mostly round or irregular shaped foci with a diameter less than or equal to 3cm, and can be categorized as benign and malignant according to the benign or malignant nature of the nodules. Benign nodules can be caused by infections and other reasons, and malignant nodules are mainly primary tumors of the lungs as well as metastatic tumors of the lungs. Screening of people at high risk of lung cancer without symptoms, the incidence of lung nodules is 23%, 29%, and 35.5% in North America, Europe, and East Asia, thus it is clear that only some of the people have lung nodules. When lung nodules are present, it is important to seek prompt medical attention to clarify the cause of the disease and treat accordingly to avoid delays.