Preoperative preparations for coronary angiography are as follows: 1. The relevant tests requested by the doctor should be completed before the operation; 2. The doctor should be informed of all medications currently taken before the operation; 3. Loose fitting hospital gowns should be changed before the operation to facilitate the operation; 4. Adequate rest should be taken the night before the operation without excessive tension; 5. Drink more water and intravenous fluids for hydration to reduce the occurrence of organ damage; 6. Any discomfort before or during the operation should be promptly informed to the medical staff for treatment.