Small 5mm ground glass nodules in the lungs are mostly caused by benign diseases and most of them are not serious; however, they can be malignant and are more serious if they are malignant. Lung nodules can be caused by a wide range of benign and malignant lung diseases, with different nodule sizes, densities, and morphologies, and varying degrees of severity. A 5mm ground glass nodule is a small nodule, mostly caused by benign diseases such as pneumonia, tuberculosis, etc. The nodule has clear boundaries, uniform density and smooth edges, and after regular and effective anti-infection and anti-tuberculosis treatments, the inflammatory nodule will gradually shrink or even disappear completely, which is generally not serious. If the 5mm ground glass nodule in the above treatment process or regular follow-up process, cough, cough sputum and other respiratory symptoms do not improve, but the nodule continues to grow, the edge of the rough, lobulated, infiltrative growth, or pulling the pleura, should be highly suspected of malignant nodules, at this time it is more serious. The presence of 5mm ground-glass nodules in the lungs, it is recommended that patients consult a specialist in a timely manner, and follow the doctor’s instructions for follow-up, examination or treatment.