Nodules 5mm in size under the pleura of the lower lobes of the lungs are small nodules, and are generally not considered serious if they are not malignant. Clinically, lung nodules are usually categorized into solid nodules, pure ground-glass nodules, and partially solid nodules, and partially solid nodules are generally the most malignant. Patients with ground-glass nodules that are less than 5 mm are mostly benign with chronic inflammatory changes. If there are no clinical symptoms, generally do not need special treatment, patients only need to go to the hospital regularly 6-12 months to review the chest CT can be. If the patient’s lung nodules show growth changes, especially small nodules with lobulation, short burr, pleural pulling sign and other changes, the patient should be alert to the occurrence of early lung cancer. If necessary, chest enhancement CT and percutaneous lung biopsy should be performed to find out whether the small nodule of 5mm has early lung cancer changes. Once diagnosed, patients should actively cooperate with the thoracic surgeon to perform early surgical resection of the lesion to avoid missed diagnosis and misdiagnosis.