The China Cardiovascular Disease Report 2014, just released on August 7, 2015, shows that cardiovascular disease accounts for more than 40% of all deaths in China; and early diagnosis and treatment of coronary artery disease can significantly reduce the mortality rate of patients. Coronary angiography has long been the “gold standard” for diagnosing coronary heart disease because it can clearly show the narrowing of the lumen caused by atherosclerosis of the heart’s coronary arteries, but this test is an invasive test with relatively high risks and costs. Multi-layer spiral CT, on the other hand, has rapidly gained clinical recognition because of its fast scanning and powerful post-processing capabilities, which enable two- and three-dimensional imaging of coronary arteries in a non-invasive manner. Coronary CTA is an examination method of imaging the coronary arteries of the heart by using spiral CT scan after intravenous injection of contrast agent, and then reconstructed by computer processing, which can clearly show the anatomical structure and the wall and lumen of the coronary arteries. As a powerful tool for diagnosing coronary artery diseases, coronary CTA can not only detect stenosis and calcification of coronary arteries, but also evaluate abnormalities of coronary artery origin alignment, valvular disease, and precordial disease. Because of its non-invasive, safe, easy, painless and low cost features, coronary CTA is increasingly accepted by patients as a screening test for the diagnosis of coronary artery disease. There are more indications for coronary CTA, including high-risk groups prone to coronary artery disease – those with risk factors such as hypertension, diabetes, hyperlipidemia, family history of coronary artery disease and smoking; abnormalities in exercise ECG examinations, unexplained chest pain, patients with coronary artery disease but unwilling or unsuitable for traditional coronary artery vascular Patients with regular follow-up of angiography; patients who are reviewed after stent implantation and coronary artery bypass grafting are all feasible for diagnostic coronary CTA, which can also be used as a routine examination of atherosclerosis. A meta-analysis in JAMA 2009 found that the radiation dose of coronary CTA was about 4.6-30.1 mSv. In recent years, low-dose scanning techniques have been developed, such as intelligent coronary serial scanning, large-pitch dazzle scanning technique, CARE kV technique, and SAFIRE iterative reconstruction. SAFIRE iterative reconstruction and other technologies are widely used to help physicians apply coronary CTA technology more safely for the benefit of the majority of patients. Based on the application of these new technologies, our hospital selects a reasonable tube voltage and contrast flow rate according to the patient’s BMI and heart rate, realizes personalized scanning methods, and minimizes the radiation dose and the amount of contrast agent for patients on the basis of ensuring image quality, and has achieved good results. radiation dose from nature (3.1mSv).