Reading an X-ray film requires a wealth of anatomical knowledge as well as imaging knowledge: first we come to a general understanding of how to see the X-ray film, to understand the basic principles of X-ray photo formation. For example, the density of various tissues in the human body will have certain differences, in the X-ray film will show a different color, generally containing gas tissue, such as the lungs, trachea and gastrointestinal tract, etc., will be shown as black. Some soft tissues, such as the heart, liver, kidneys, muscles and other organs, will appear gray, while bone tissue generally appears white. Secondly, we need to understand the order of reading the film, generally from top to bottom, from outside to inside, from front to back, from large to small, from the beginning to the end. Then we should pay attention to the distribution and location of the lesion, the size and number of lesions, and the relationship between the density, margins, and morphology of the lesion and the surrounding tissue.