Lung ground-glass nodule with light density and unclear boundary is a description of the lesions in the lungs in CT examination, and the main causes of the corresponding conditions are inflammation, alveolar hemorrhage and early tumors. 1. Inflammation: Generally, bacterial, mycobacterial infection or allergic pneumonia may cause the corresponding changes, which are closely related to the exudation caused by inflammatory stimulation. 2. Alveolar hemorrhage: generally related to trauma and abnormal coagulation function, and the emergence of alveolar hemorrhage will cause the corresponding conditions. 3. Early stage tumor: early stage tumor cells are not dense and grow in the alveoli, which will show corresponding changes. In the case of ground-glass nodules, regular observation under the guidance of clinicians or puncture biopsy should be paid attention to, and standardized treatment should be done after confirming the pathological results.