The risk of malignancy is high for 20mm ground glass nodules, which are serious if caused by malignant tumors and mostly less serious if caused by benign diseases. Lung nodules can be categorized according to their density into solid nodules, pure ground glass nodules nodules and mixed ground glass nodules. Mixed ground-glass nodules are nodules with both solid and ground-glass components, also known as partially solid nodules, and have a high risk of malignancy, about 64%. Pure ground glass nodules nodules also have a high probability of malignancy, about 18%. The malignant risk of lung nodules is also related to the size of the nodules, the probability of malignancy of 20mm nodules is about 75%. 20mm ground glass nodules have a higher probability of malignancy, and if they are caused by malignant tumors such as bronchopulmonary carcinoma and metastatic carcinoma of the lungs, the condition is serious and may be life-threatening, while if they are caused by lung misshapen tumors, pneumonia and tuberculosis, they can be improved or cured with timely treatments and are therefore mostly not serious. It is recommended that patients should consult a doctor in time and choose follow-up, biopsy or surgery according to the advice of specialists and their own wishes.