With the popularity of CT examinations, ground glass nodules in the lungs are being detected at an increasing rate. The likelihood of malignant changes in ground glass nodules in the lungs varies with the size of the nodule. For nodules less than 4 mm in diameter, the chance of developing lung cancer is generally less than 1%, regardless of whether they are ground glass or solid nodules. For nodules larger than 8 cm, the incidence of lung cancer is higher, about 50% or more. In general, if the nodule is larger than 8 cm, further examination is needed to clarify it. The patient has a history of specific occupational exposure, such as a history of ammonia exposure, comorbid chronic diseases, including a family history of tumor disease. For these high-risk patients, the possibility of malignant lesions is very high, and early biopsy or further PET-CT examination is recommended to clarify the diagnosis. For nodules smaller than 8 cm, regular follow-up and dynamic observation are recommended. If, during the follow-up process, the solid component of the nodule changes from a ground glass component to a mixed component, such as a mixed solid component, or a completely solid nodule, the possibility of malignancy is very high and further treatment is recommended.