X-ray diagnosis is one of the important clinical diagnosis methods, and the diagnosis is based on X-ray images. Therefore, it is necessary to carefully observe the X-ray images, distinguish normal from abnormal, synthesize various pathological manifestations on X-ray, and analyze and reason with clinical data, including medical history, symptoms, signs, and other clinical examination data, in order to come up with a more correct X-ray diagnosis. Therefore, the accuracy of X-ray diagnosis depends to a considerable extent on the understanding of the characteristics of X-ray images and their anatomical-pathological basis and the correctness of the diagnostic thinking method. In order not to miss the important X-ray signs, a comprehensive and systematic observation should be carried out in a certain order. For example, when analyzing the chest X-ray, attention should be paid to the thorax, lungs, mediastinum, diaphragm and pleura. In addition, we should focus on one of these aspects in the clinical context. When analyzing the lung film, the lung should be observed from the tip to the base of the lung and from the hilum to the periphery of the lung in order. In the process of observation and analysis, care should be taken to distinguish normal from abnormal. When observing abnormal X-ray manifestations, attention should be paid to its location, distribution, number, shape, size, margins, density, its uniformity and functional changes of the organ itself and changes in the adjacent organs and tissues of the lesion.