The diagnosis of coronary artery disease mainly includes: 1.History inquiry and physical examination: including the inquiry of risk factors and clinical symptoms (such as angina pectoris, myocardial infarction or heart failure, etc.). 2.Electrocardiogram: including resting ECG, ECG stress test and dynamic ECG. 3.Biochemical marker test: such as cardiac enzyme profile, troponin, etc. 4.Imaging: including echocardiography, radionuclide examination, X-ray examination, selective coronary angiography (referred to as coronary angiography), etc. Among all the methods to diagnose coronary artery disease, coronary angiography is the most reliable method and the main means to diagnose coronary artery disease at present. This method can be used to visualize the diameter, course, distribution and morphology of the coronary arteries, and to understand the smoothness and elasticity of the vessel wall, the presence of stenotic lesions, and the extent, location, length, number and characteristics of the lesions (such as whether there is calcification, thrombosis, ulceration, aneurysm, intimal entrapment, whether the lesions are angular and located at bifurcation vessels, and whether they are eccentric or concentric). These characteristics are very important for selecting the indications for intervention, determining the success rate of intervention, and choosing the appropriate timing, instruments and methods of intervention. These characteristics are very important for selecting the indication for intervention, determining the success of intervention, and choosing the appropriate timing, instrumentation, and method of intervention, because interventional treatment of coronary artery lesions is performed by hand outside the patient’s body. Therefore, coronary angiography is the gold standard for the diagnosis of coronary artery disease, and it is a prerequisite for the successful completion of coronary interventions to fully reveal all coronary artery lesion features through angiography.