Chest X-ray is the most routine physical examination for checking the chest, which itself can check the condition of lungs, ribs and mediastinum, and the diseases that can be examined include lung cancer, tuberculosis, pneumonia, rib fracture, and congenital heart disease, and so on. 1. Lung cancer: through chest X-ray, it can be found that there is a high-density mass in the lungs with uneven edges, affecting the airways and mediastinum. 2. Tuberculosis: polymorphic foci can be found in the lungs through chest X-ray examination, and fibrosis and calcification can be found, which preferably occurs in the apical and posterior segment of the upper lobe of both lungs as well as the dorsal segment of the lower lobe. 3. Pneumonia: In lobar pneumonia, chest radiography shows solid changes in the lung tissue. 4. Rib fracture: Chest X-ray can observe the rib alignment, and fracture can be diagnosed by the presence of cortical discontinuity of the ribs. 5. Congenital heart disease: abnormal heart shape, change of mediastinum shape and abnormal cardiothoracic ratio can be found through chest radiography. Chest X-ray can also diagnose pneumoconiosis, abnormal lung development and metastatic tumor. Chest X-ray is only a preliminary screening, further examination needs to be combined with CT and ultrasound to make a comprehensive judgment, if necessary, also need to do laboratory tests and pathological puncture biopsy, in order to diagnose the specific conditions after the standardized treatment.