Congenital cysts of bronchogenic origin are common in children and are located in the interstitium or mediastinum. Because the cysts can be single or multiple, containing different amounts of gas or fluid, and thus can present different manifestations on chest X-ray: 1, single fluid, gas cysts are the most common, the size of the cyst varies, and can be seen as a round, thin-walled cyst, with a fluid surface inside. This kind of cyst is characterized by thin cyst wall, no inflammatory infiltration lesions in the adjacent lung tissue, fibrous changes are not much, need to be differentiated from lung abscess, tuberculosis cavity and lung cysts. On X-ray, the wall of lung abscess is thicker and the surrounding inflammation is obvious, while tuberculosis cavity has a longer history and is surrounded by tuberculosis satellite foci. Pulmonary cysts have epidemiologic regional characteristics, life history and occupational history, blood image, intradermal test, etc. help to identify. 2.Single pneumocysts The chest radiographs show that the lungs on the diseased side contain pneumocysts. Huge pneumocysts can occupy one side of the thoracic cavity, compressing the lungs, trachea, mediastinum, and the heart, and need to be differentiated from pneumothorax. Pneumothorax is characterized by lung atrophy pushed toward the lung door, while the air of the pneumocystoma is located in the lung, often carefully observed in the lung apices and costal septal angle can be seen lung tissue. 3.Multiple air cysts Clinically also more common, chest radiographs show multiple air cysts of different sizes and uneven edges, which need to be differentiated from multiple pulmonary herpetomas. Especially in children, pulmonary blisters are often accompanied by pneumonia and are characterized by translucent round thin-walled blisters and their variability in size, number, and morphology on X-ray. More changes are seen with each short-term follow-up, and sometimes they can enlarge rapidly or rupture and form a pneumothorax. Once the lung inflammation subsides, the blisters can sometimes shrink or disappear on their own. 4.Multiple fluid and gas cysts can be seen as multiple fluid and gas cavities of different sizes on chest radiograph. Especially if the lesion is located on the left side, it needs to be differentiated from congenital diaphragmatic hernia, which can also be presented as multiple liquid flat, oral iodine oil or dilute barium examination if necessary, and septal hernia if the contrast agent is seen entering the gastrointestinal tract in the thoracic cavity.