A 3cm lung nodule does not necessarily require immediate surgical treatment, but requires comprehensive judgment, and if it is a malignant lesion, it needs to be surgically removed as soon as possible. Lung nodules have more causes, 3cm lung nodules may be malignant tumors or benign lesions such as common infections, Mycobacterium tuberculosis infections, tuberculomas and so on. 3cm lung nodules need to be reviewed regularly to observe their dynamic changes. If the newly appeared nodule exists with burr edges, obvious lobulation, and vacuolar sign, etc., it is considered that there may be a risk of malignant lesions, and further pathological examination is needed. Lung nodule 3cm is found, it is recommended that the patient go to the regular hospital as soon as possible, and actively cooperate with the doctor’s diagnosis and treatment.