The preparatory work for cardiography includes blood test, auxiliary examination, preoperative conversation and dietary preparation. 1. Blood test: improve blood routine, liver and kidney function, electrolytes, blood sugar and blood fat, hepatitis and syphilis and other infectious diseases, and if necessary, improve blood type test. 2. Auxiliary examination: including electrocardiogram, chest X-ray, cardiac ultrasound, dynamic electrocardiogram and so on. 3. Pre-operative conversation: before the imaging, we must have a conversation with the family members or the person himself, the main contents include the operation method, the operation risk, and the stent implantation may be needed if necessary. 4. Dietary preparation: Pay attention to a light diet before the examination, and fast for 4 to 10 hours before the operation. Cardiography is an invasive test, which is the gold standard for the diagnosis of coronary atherosclerotic heart disease and must be performed in a regular hospital.