Frosted glass nodules are a special type of manifestation of frosted glass shadows, which are mainly caused by differences in size, manifestations on different imaging devices and different diseases. Different sizes: FGNs are mainly round or irregular lesions less than or equal to 3cm, and when they are larger than 3cm, they are also called ground-glass shadows. Imaging equipment performance is different: ground glass nodules manifested as a slightly dense shadow in the lungs, and does not cover the blood vessels, mainly in the ct manifestation, in x-ray is generally difficult to find. On the other hand, because of its size, it can be detected on chest x-ray. Diseases caused by different: Ground glass nodules are mainly seen in tuberculosis, limited pulmonary fibrosis, peripheral lung cancer, etc., while ground glass shadow is mainly seen in pulmonary edema, acute respiratory distress syndrome. Both ground-glass nodules and ground-glass shadows are abnormal manifestations in the lungs, and should be diagnosed and treated in the hospital to clarify the cause of the disease.