A 3mm ground glass nodule is not serious and is most often the result of benign disease such as pneumonia, and there is only a very small risk that it is the result of lung cancer, which is usually earlier and not very serious. Lung nodules are imaging manifestations of a wide range of benign and malignant lung diseases, and the size and density of lung nodules can be used to initially assess the risk of malignancy. Milled glass nodules are lung nodules that contain a milled glass component (cloudy slightly dense shadow on chest CT), of which pure milled glass nodules have a slightly higher risk of malignancy, at about 18%, while mixed milled glass nodules have a high risk of malignancy, at about 63%. Generally 3mm lung nodules have almost no risk of malignancy. Therefore, 3mm ground-glass nodules are mostly caused by benign diseases such as pneumonia, charcoal deposition, focal fibrosis, etc. Most of them are not serious, and can be improved or cured by timely treatment, and only a few patients with severe pneumonia and tuberculosis have serious conditions. Only a few patients with severe pneumonia or tuberculosis have serious conditions. 3mm ground-glass nodules only have a very low risk of being caused by lung cancer, which has a certain degree of severity, but due to the small size of the lesion, even if it is lung cancer, it is still in the early stage and has a better prognosis when treated in time, so it is not a serious condition on the whole. Patients are advised to seek timely medical consultation, consult a specialist, and follow up and treatment as prescribed by the doctor.