Isolated pulmonary nodules are defined as a single, well-defined, image opaque lesion less than or equal to 30 mm in diameter, surrounded by air-containing lung tissue, with no manifestations of pulmonary atelectasis, hilar enlargement, or pleural effusion. The incidence rate is about 150,000 new cases per year in the United States, and there are no accurate statistics in China. However, China is currently the largest country in lung cancer, and its incidence rate must greatly exceed this figure. II. Etiology Isolated lung nodules are divided into two major categories: benign and malignant lesions. Malignant diseases mainly include: adenocarcinoma of the lung, alveolar carcinoma of the fine bronchus and squamous cell carcinoma of the lung. Benign diseases include: pulmonary malignancy, pulmonary sclerosing hemangioma, pulmonary inflammatory pseudotumor, pulmonary tuberculosis ball, pulmonary varicose ball, and vascular follicular lymphadenopathy. Although pulmonary sclerosing hemangioma is benign, it often recurs and therefore has a malignant tendency. III. Treatment Patients with isolated nodules in the lung are increasingly desperate for an accurate diagnosis. In order to save more lives, it is important not to miss any suspicious lesion once it is detected. In practice, the measures that can be taken after the detection of a suspicious nodule must be one of the five or a combination of these measures: CT, PET, CT-guided fine-needle aspiration biopsy, surgery, or observation and follow-up. However, each of the five methods has its own advantages and disadvantages; CT is highly sensitive but slightly less specific, PET is sensitive and specific but expensive, and neither can provide a pathologic diagnosis; fine needle aspiration can often determine the nature of the pathology, but it is invasive and sometimes the diagnosis cannot be confirmed due to sampling and other reasons. Thoracoscopic biopsy of masses is one of the effective means to confirm the diagnosis of small nodules in the lung, which is relatively less invasive and can clearly diagnose and remove lesions. However, it tends to be a prudent choice of surgery for benign nodules; follow-up observation undoubtedly avoids non-essential surgery, but may delay the diagnosis of malignancy at a greater cost. Therefore, the most reasonable, safe and economical treatment measures should be formulated according to the patient’s lesion and actual situation.