The choice of X-ray examination methods should be based on an understanding of the indications, contraindications, advantages and disadvantages of various X-ray examination methods. According to the preliminary clinical diagnosis, the X-ray examination program should be proposed, and usually the safe, accurate, simple and economical method should be chosen. Therefore, in principle, plain films should be considered first, and imaging should be considered only if necessary. However, it is not absolute, sometimes 2-3 examination methods are necessary. For example, for certain patients with congenital heart disease who are ready for surgical treatment, not only chest fluoroscopy with plain films, but also cardiovascular angiography is necessary. For the examination methods that may produce certain reactions and have certain risks, the selection should strictly grasp the indications, and should not be abused as a routine examination, so as not to bring pain and losses to the patients.