Pulmonary occupancy is an imaging concept that does not refer to a specific disease, it is an imaging change. A right pulmonary occupancy literally refers to the presence of an occupying lesion in the right side of the lung. An occupying lesion means that it is not a tissue that exists in the lung itself, but an emerging lesion that is mostly substantial and generally has the following conditions: i. Infectious lesions in the lung, mostly chronic lung infections that appear as granulation tissue or form keloid tumors; ii. Right lung cysts can also manifest as right lung occupancy, and lung cysts are benign lesions that do not require treatment as long as they are not co-infected; iii. benign tumors, including pulmonary hemangioma, cellular adenoma and nodular hyperplasia; iv. malignant tumors of the lung, mainly referring to lung cancer. Right lung occupancy indicates the existence of a substantial lesion in the lung, which needs further examination to clarify its nature, and malignant tumors should be treated early.