Coronary artery disease is a group of diseases caused by the narrowing and occlusion of the coronary arteries (coronary arteries), the blood vessels that supply blood to the heart, and their branches. Identification of the location, nature and degree of stenosis of coronary artery lesions is extremely important for treatment and assessment of prognosis. The most commonly used imaging tests to evaluate coronary artery lesions include selective coronary angiography and coronary CT. The two are both interrelated and distinct. With coronary angiography, a catheter is sent to the heart through an artery at the wrist or thigh root, and contrast is injected into the coronary arteries to visualize the lesions in the coronary lumen. Because of the accuracy of the information, coronary angiography is now the “gold standard” for the diagnosis of coronary heart disease in clinical practice. However, coronary angiography also has shortcomings. In addition to the higher cost, the most important is that the catheter must be inserted into the body through a puncture, which is an invasive operation and may cause damage at the puncture site, through the arteries, coronary arteries or even the whole body. Coronary CT is a non-invasive examination method, which actually scans the coronary arteries by multi-row spiral CT (MDCT for short) to understand the coronary lesions. Since the first 4-row MDCT was introduced internationally in 1998, after the development of 8, 16 and 32 rows, the most advanced MDCT in clinical practice has reached 512 rows. The “rows” refers to the number of arrays of CT scanner detectors. Generally, the more rows, the wider the detector width, and the greater the width of a completed scan. In addition to being non-invasive, coronary CT also has advantages over coronary angiography for measuring coronary calcified plaque load, understanding coronary vessel walls and extra-coronary conditions, and examining congenital coronary artery developmental abnormalities. Coronary CT also has shortcomings, such as unclear images when the heart rate exceeds 70 beats/min, arrhythmia or heart failure; less clarity and accuracy than coronary angiography, which does not adequately show fine branches of the coronary arteries; less dynamic observation of coronary blood flow than coronary angiography; and limited assessment of in-stent restenosis of the coronary arteries. Most importantly, coronary CT is only an examination tool, while coronary angiography can simultaneously perform interventional treatment for suitable lesions. Therefore, in brief, coronary CT can be chosen for patients who cannot undergo coronary angiography and are not clinically inclined to coronary artery disease but need to rule out coronary artery disease and evaluate the efficacy after intervention or bypass surgery; while coronary angiography should be preferred for patients with high clinical suspicion of coronary artery disease who are likely to need simultaneous interventional treatment. Finally, it should be added that although coronary CT is a non-invasive examination, it also requires X-rays for imaging. It has been observed that for each coronary CT test, the radiation dose received by the patient is equivalent to that of 500-700 X-ray chest films, and the incidence of tumors due to radiation will increase by 9%! Therefore, do not repeat this test simply because coronary CT is non-invasive, but, of course, do not worry too much if it is really needed.