People often find occupying lesions in the lungs during physical examination or chest examination for other conditions, ranging from the size of a bean to half of the chest cavity, and sometimes benign and malignant cannot be well identified, which causes a lot of trouble and fear to patients and their families. Isolated lesions can be formed in the lung for various reasons, and the common ones are as follows: peripheral lung cancer, pulmonary adenoma, pulmonary smooth muscle tumor, pulmonary malformation tumor, multiple pulmonary metastases, pulmonary tuberculosis ball, pulmonary inflammatory pseudotumor, spherical pneumonia, pulmonary abscess, pulmonary fluid-containing cyst, pulmonary cysticercosis, pulmonary artery aneurysm, and traumatic hematoma, etc. Among them, peripheral lung cancer, pulmonary tuberculosis ball, and pulmonary inflammatory masses are most common. To determine the nature of the lesion is quite important for the choice of treatment plan. Identification of the nature of the mass must be combined with X-ray and clinical manifestations and necessary laboratory tests, and sometimes it is necessary to perform mass puncture, and different puncture methods should be used for different lesion locations. Those close to the pulmonary hilum can be biopsied by fiberoptic bronchoscopy for cytological examination under microscopic magnification to a certain magnification, and in individual cases firming at the molecular level (e.g., immunohistochemistry, etc.) is done by the pathology department. The new magnetic resonance imaging technology also plays an important role in the diagnosis of lung occlusions. PET is a kind of positron emission computed tomography, which is a better test to identify benign and malignant tumors, and it is also more expensive. Through these examinations, some valuable information can be found to help clinicians make diagnosis and correct treatment plan. Some lesions are difficult to distinguish benign from malignant for a while, and need dynamic observation for a period of time or observation of lesion changes after treatment. sometimes it is necessary to obtain the lesion in surgery after opening the chest for rapid pathological examination, and the exact diagnosis of the lesion can usually be completed after half an hour, and the scope of resection of the lesion and whether to clear the lymph nodes can be decided on the operating table. after 40 years old, unexplained cough, especially when it is with blood sputum, should be promptly examined in hospital. The need for vigilance is even greater in those with a long history of smoking.