Multiple ground-glass lung nodules up to 4mm, if it is caused by inflammatory lesions, it is usually not serious and can be cured by timely treatment; if it is caused by interstitial lesions, or carcinoma, it is relatively more serious. 1. Inflammatory lesions: lung infections caused by various pathogens such as bacteria, virus, mycoplasma, chlamydia, mycobacterium tuberculosis, because of inflammatory infiltration, exudation and tissue proliferation, there will be single or multiple ground-glass nodules, and this type of ground-glass nodules is not serious, and can be cured through regular anti-infective treatment. 2. Interstitial lesions: such as interstitial pneumonia, multiple pulmonary fibrosis, etc. caused by multiple nodules in the lungs, mostly manifested as progressive dyspnea, affecting normal life and work, and can even develop into respiratory failure, so it is more serious. However, the condition can be controlled by timely treatment. 3. Cancer: such as squamous lung cancer, lung adenocarcinoma and other malignant tumors, often in the early stage of the disease manifested as ground-glass lung nodules, if the nature of the nodules can not be clarified as early as possible, early treatment and intervention, with the progression of the disease, it will be a greater threat to the patient’s life, and there is a risk of disease and death. Ground-glass nodules are only the result of imaging examination, which cannot be used to determine the severity of the disease, and require timely review and exclusion of malignant lesions based on pathological examination or lung puncture examination, so as to achieve early diagnosis and early treatment.