Ground glass nodule in lung is an imaging manifestation, which refers to the appearance of high-density shadow with clear or unclear boundary in the lung. It may be a malignant lung tumor or benign lesion, or inflammation, etc. Whether it is serious needs to be judged according to the examination results, and the specific analysis is as follows: 1, malignant tumor: If the ground glass nodule is larger than 8mm, the boundary is unclear, and accompanied by lobar, burr sign, etc., consider the possibility of malignant lung tumor, which is more serious and the patient’s prognosis is poor. The treatment effect depends on early detection, early diagnosis and early treatment; 2. CT images mostly show multiple foci with unclear boundaries and various morphologies; for example, the intrapulmonary images of pulmonary tuberculosis can show the inverse halo sign with clusters of small nodules. For example, intrapulmonary images of pulmonary tuberculosis may show a reverse halo sign, with clusters of small nodules and large morphological differences between lesions.