There are many methods to examine coronary artery disease, which are roughly divided into two categories: one is to check whether there are signs of myocardial ischemia, including electrocardiogram, ambulatory electrocardiogram (Holter), echocardiogram, nuclear myocardial imaging, etc. These tests cannot observe the condition of coronary arteries, but diagnose coronary artery disease by determining whether there is myocardial ischemia; the other is to directly examine whether there are lesions such as stenosis and obstruction in coronary arteries, including Coronary CT, magnetic resonance imaging (MRI), intravascular ultrasound of coronary arteries (IVUS), coronary angiography and so on. Among them, coronary angiography and intracoronary ultrasound are invasive examinations, while the rest are non-invasive examinations. Patients can choose different examination methods according to their financial conditions and the needs of their conditions, and with the advice of their doctors.