Chest CT can detect lesions early and combine with CT imaging features to diagnose possible diseases. It can diagnose early lung tumors, localize and diagnose the lung segment where the lesion is located, the relationship between the lung lobes and the central bronchus, and facilitate further examination. For peripheral lesions, lung puncture can be taken, and for central lesions, bronchoscopy is feasible, or for patients who can be operated on, preoperative evaluation and confirmation of diagnosis can be performed. For non-neoplastic lesions, the differential diagnosis of interstitial lung disease, lung infection, and interstitial disease is mainly characterized by lattice-like manifestations involving the interstitium, or exudative solid changes involving the alveoli, with subpleural or peribronchial parenchymal changes, rather than lung segmental or lobar changes. Pulmonary infection, with a predominantly lobar or lobular solid manifestation, with or without pleural effusion, with or without cavitation, with or without tree-bud-like changes, with or without bronchodilatation-like changes, etc. Assessment of the possible causative organisms, assessment of the developmental changes, assessment of the response to treatment and prognosis of the disease, etc. Identification of central airway diseases, central airway lesions such as airway stenosis, airway foreign bodies, and airway tumors can be identified very visually through three-dimensional reconstruction of the airway, which provides a basis for further treatment.