Lung cancer is a common malignant tumor of the respiratory system. Central type lung cancer refers to lung cancer occurring in bronchi, lobar bronchi and lung segmental bronchi, with squamous lung cancer and small cell carcinoma predominating. The imaging manifestation of central lung cancer mainly includes the following two aspects: 1. X-ray manifestation, which is a mass in the hilar region of lung under X-ray, and the shape of the mass is often lobulated; when the mass causes partial or complete obstruction of bronchus, indirect X-ray imaging manifestation of central lung cancer such as obstructive emphysema, obstructive atelectasis, obstructive pneumonia, etc. 2. CT manifestation, in which central lung cancer It can obviously show the mass in the bronchial lumen, the thickening of the wall, narrowing of the lumen and the shape and contour of the mass in the lung field, the internal situation and the metastasis of the mediastinal lymph nodes in the lung gate.