Coronary CT imaging is a new technology that has emerged only in recent years, especially after the advent of 64-row spiral CT, which is widely used. Coronary CT is no different from a normal enhanced CT examination, in that the contrast is fed into a vein in the arm, just like a usual infusion, and then the heart is scanned and the coronary arteries are reconstructed by software. It is therefore almost non-invasive and very safe. 64-row spiral CT has high sensitivity and specificity for the diagnosis of coronary artery lesions, but there are also better 128-row CT and dual-source CT, which are more effective for coronary artery imaging. Most of the judgments of coronary CT on coronary artery stenosis are similar to coronary angiography, except that there are a few exaggerated or reduced effects on stenosis, such as lighter stenosis and slightly heavier display. If coronary CT shows normal coronary arteries, you can basically be sure that there is no stenosis in the coronary arteries, and there are very few cases of false negatives. However, coronary CT cannot be fully equated with coronary angiography. Coronary angiography sees the lumen of the vessel, while coronary CT sees not only the lumen but also the wall of the vessel, so coronary CT provides more information. Coronary CT can understand the nature, size, softness, calcification, length, and extent of the arterial plaque. There is a congenital variant called myocardial bridge, which is a part of the coronary artery penetrating in the myocardium. This variant can also cause angina pectoris, and coronary CT is sensitive to myocardial bridge and can clarify its diagnosis. Meanwhile, the examination of coronary CT can be a guide for the interventional treatment of coronary artery disease. Therefore, CT coronary angiography is very suitable for screening or review of coronary artery disease, or even physical examination, because some patients with coronary artery stenosis are clinically asymptomatic. It can be said that coronary CT is a scout for coronary artery disease, but because the temporal resolution (up to 40 ms) and spatial resolution (up to 0.4 mm) of 64-row spiral CT are still inferior to coronary angiography, the current “gold standard” for coronary artery lesion diagnosis, and because of the constant beating of the heart and the millimeter size of the coronary arteries, it is difficult to make the coronary arteries look like a coronary artery. With the constant beating of the heart and the millimeter diameter of the coronary arteries, it is not easy to make the images of coronary angiography meet the diagnostic requirements. The preparation before the examination and the precautions during the examination are crucial to ensure the image quality. (1) The heart rate of the subject should be controlled to less than 70 beats/min. If the heart rate is too fast, oral heart rate control drugs, such as betalactam, should be taken under the guidance of the doctor before the examination. Arrhythmias should be controlled by medication before this test. Atrial fibrillation, occasional atrial and ventricular precontractions, and more severe sinus arrhythmias (heart rate changes of more than 5 beats per minute) can have a significant impact on the reconstructed image, and despite personalized post-processing, the image used for diagnosis often only meets the criteria of grade 3. (2) A 4-hour fast is required before the examination. (3) Patients with iodine allergy and severe liver and kidney disease are contraindications. Nowadays, in most cases, iodine allergy test is not done before coronary CT examination, but iodine allergy test should be performed before the examination for patients with allergies. The high radiation dose of coronary CT has also caused some patients to be concerned about this test. Doctors do not send patients for coronary CT as often as they do for electrocardiograms and echocardiograms, but probably once a year should not be too much. In addition, the technology of CT is rapidly evolving and the amount of radiation will only decrease and never increase. Given all the benefits of coronary CT, can coronary CT replace coronary angiography? Which is more important, anatomical or functional imaging of coronary arteries, has been a controversial topic in the field of coronary artery disease diagnosis. Coronary CT imaging also has its obvious shortcomings, such as the accuracy of coronary CT decreases significantly in the presence of severe calcified lesions in the coronary arteries. For patients with arrhythmias, especially atrial fibrillation, it is a major blind spot for coronary CT examination. Compared with coronary angiography, the current 64-row spiral CT has a high false positive rate, resulting in a relatively low positive predictive value (<80%). Both interventional cardiologists and cardiac surgeons need to have a precise understanding of the anatomy of the coronary arteries to determine the strategy of revascularization therapy, which cannot be solved by the current coronary CT, which is expected to challenge coronary angiography in the future by improving the resolution of stereo and time. Moreover, if coronary artery stenosis is detected by coronary angiography, direct interventional treatment can be performed, which is not possible with coronary CT imaging.