Coronary angiography uses the imaging effect of an angiography machine to visualize the coronary arteries by percutaneously puncturing the radial artery at the wrist or the femoral artery at the root of the thigh (less than 5%), retrograde a special contrast catheter through the aorta to the root of the ascending aorta, then explore and align the left or right coronary artery orifice, and inject the contrast agent at several different projection angles. In this way, the lumen of the coronary artery trunk and its branches can be clearly visualized, not only to understand whether there is a stenotic lesion in the coronary artery, but also to make a more comprehensive and clear judgment on the location, extent, severity, and condition of the vessel wall, and to decide the next treatment strategy (drug therapy alone, interventional therapy, or coronary artery bypass grafting in cardiac surgery), and to determine the efficacy of the treatment. It can also be used to determine the efficacy of the treatment. Overall, the diagnostic value of percutaneous coronary angiography is better than that of coronary CT. Coronary angiography can be considered in the following clinical situations: 1. unexplained chest pain, clinical suspicion of coronary artery disease, non-invasive tests cannot confirm the diagnosis; 2. unexplained arrhythmia, sometimes coronary angiography is needed to exclude coronary artery disease; 3. unexplained left heart insufficiency; 4. asymptomatic but suspected coronary artery disease; 5. Stable angina pectoris or old myocardial infarction, with poor results in improving lifestyle and best drug therapy, affecting quality of life; 6. Unstable angina pectoris, especially those clinically judged to be at high risk, may be directly treated with coronary angiography; 7. Asymptomatic coronary artery disease, especially patients with positive exercise test and obvious risk factors; 8. Acute myocardial infarction within 6 hours of onset or more than 6 hours of onset still with Persistent chest pain and proposed emergency coronary artery recanalization; 9. Patients with moderate or higher stenosis or unstable plaque in coronary arteries found or highly suspected by imaging such as coronary CT angiography; 10. Patients with congenital heart disease and valve disease before major surgery; 11. Patients with successful resuscitation of primary cardiac arrest who require evaluation of coronary arteries and early intervention of vascular lesions if necessary; 12. Patients with percutaneous coronary intervention or coronary artery bypass graft Recurrent angina after treatment or coronary artery bypass grafting. In patients who undergo coronary angiography via radial artery puncture, the sheath can be removed immediately after the procedure, and then the compression bandage or wide tape can be removed after 4-6 hours of local compression of the puncture site, which basically does not affect the activities of the extremities and life, and can even be discharged on the same day after the procedure. In the case of femoral artery access, the sheath can also be removed immediately after surgery, and the compression bandage will be applied after 20 minutes of routine compression of the puncture site, which requires lower limb braking for 24 hours to start light activities and bring some inconvenience to life. However, in our department only about 2% of coronary angiograms are currently required to be performed via the femoral artery.