Abstract: There are different variations in the branching pattern of the Aortic Arch (AA). The aim of the present study was to study and evaluation of anatomic variations of aortic arch branches and relationship with diameter of aortic arch by 64-row computed tomography angiography (CT angiography). This descriptive analytical study was performed on 503 human by using of CT Angiography (CTA) to evaluation of anatomic variations of aortic arch. Patients underwent three dimensional restoration of aorta arch images and its branches using MIP and VRT software following intravascular injection of vein material (100 mL) and conducting CT. Then, kind of their divisions were registered. Additionally, diameter of aorta arch was measured at its cross section immediately before and after separation of its first and last branches, respectively. This study was performed on 503 specimen that 269 (53.5%) was male and 234 (46.5%) was female. The most common AA branching pattern was found in 346 (68.8%) of 503 specimens. There was no significant correlation between sex and type of variations (p = 0.073). There was no significant correlation between type of AA variations and AA diameter in the early branching area (p = 0.446) and there is no significant correlation between type of AA variations and AA diameter in the last branching area (p = 0.887). The different branching patterns of the AA observed in this study and the morphometric measurements taken can assist doctors in performing safe and effective surgeries in the superior mediastinum and also a safe interventional procedures.