Pulmonary nodules are classified as solitary or multiple. Multiple small nodules can occur in one or both lungs, and their etiology is complex and can be caused by tuberculosis, pneumoconiosis, malignant neoplasm, fungal infection of the lung, sclerosing hemangioma, sarcoidosis, and nodular disease. Multiple nodules in the lungs are more often benign and can be judged based on a combination of nodule size, location, morphology and the presence of surrounding lesions. If there is no further change in the lung nodules after 3 years of follow-up, the patient can be left alone. If the lung multiple nodule lesions increase in size, surgical treatment of the main lesion can be considered.