This paper reviewed 1 case of chronic total occlusion of right coronay artery(RCA) undergoing the interventional treatment guided by real-time fusion technique of 3D-computed tomographic angiography(CTA) and coronary angiography(CAG) in our department. The patient was admitted to the hospital due to unstable angina pectoris. CAG showed that 95% stenosis in the middle part of the anterior descending branch,70% stenosis in the distal part of the anterior descending branch, 50%-90% stenosis in the pro-ximal middle segment of the circumflex branch, then most seriously, 85%, diffuse stenosis of the right proximal segment of RCA, and the middle segment of RCA totally occluded. CTA findings indicated RCA chronic total occlusion and predicted the severity of opening. At the same time, real-time fusion technique of 3D-CTA and CAG was used to guide the opening of chronic occlusion, and was helpful to identifying the position of the balloon and the stent. We also used contralateral contrast and micro-catheter to verify the effect of 3D-CTA and CAG fusion.