Objective To explore the value of Color Doppler ultrasound in examining angiography access before transradial coronary angiography(TRA). Methods Four hundred consecutive patients undergoing elective transradial cornary angiography were screened.They were randomly divided into ultrasound group (200 cases) and conventional group without ultrasound examination(200 cases).The primary endpoints included success rate, percentage of angiographic catheter use with different diameters, adverse events during and after the procedure (such as death, acute myocardial infarction, upper limb haematoma, osteofascial compartment syndrome, radial artery pseudoaneurysm or occlusion);the secondary endpoints were the average diameter of radial and anatomic variations of approach. Results The procedural success rates in the study group and conventional group were similar (100% vs 90%), procedure duration time[(10.7±1.0)min vs(12.5±3.5)min, P<0.05] were significantly low in both groups.Vascular complications in the study group was siginificantly lower than that in the conventional group (P<0.05). Conclusions Color Doppler ultrasound examining radial artery before coronary angiography raises success rate, reduces angiographic time, radial artery spasm, and local complication.