Since simple X-ray cannot show the coronary arteries and is not useful for the diagnosis of coronary artery disease, the only way to visualize the coronary arteries is to inject a contrast agent, hence the coronary angiography. Selective coronary angiography is performed by inserting a tiny guiding tube through a skin puncture vessel and transporting it to the opening of the coronary artery under X-ray guidance. When a contrast agent that can be imaged under X-ray is injected, the lesion of the coronary artery becomes visible at a glance. Coronary angiography is a simple and convenient way to visualize the coronary arteries, to see which vessel has stenosis, how long the stenosis is, and where there is occlusion, and is the “gold standard” for diagnosing coronary artery disease. Coronary angiography has been widely used in foreign countries, and is an important guarantee for timely and accurate diagnosis of coronary artery disease and the formulation of an active and effective treatment plan. If a blockage is found, the doctor can also immediately perform interventional treatment by dilating a balloon and placing a stent in the blockage to open up the blood vessel and restore blood supply to the heart muscle.