Lung space-occupying lesions refer to the finding of a dense shadow, usually in the form of a mass, in the lungs during a chest X-ray or CT scan. It may be caused by tuberculosis ball, or it may be caused by pneumonia, lung tumors and so on. 1. tuberculosis ball: when the patient’s lungs are infected by Mycobacterium tuberculosis, due to the tuberculosis is not effectively treated, it will cause the occurrence of tuberculosis ball, manifested as a single, round, oval smooth lesion with a diameter of more than 2cm, and surrounded by small flaky satellite foci, which is presented as a space-occupying lesion of the lungs on chest CT. 2. pneumonia: mainly caused by bacterial and viral infections, the pathogens are highly virulent and the lung tissue lesions are large in scope, presenting as pulmonary space-occupying lesions on lung imaging. 3. Lung tumors: patients may be due to genetic factors, long-term smoking, air pollution, occupational exposure and other factors, leading to the occurrence of lung tumors, when patients develop lung tumors, it will also cause occupational lesions in the lungs. It is recommended that patients should seek medical examination in time to clarify the cause of the disease and then take appropriate treatment under the guidance of doctors.