Objective To study the effects of different implantation angles of bi-leaflet mechanical heart valve (BMHV) on swirling flow in the aorta. Methods Based on the aortic CT images of a healthy volunteer, the effects of 4 different valve implantation angles (0° , 45° , 90° and 135°) on the aortic rotational flow under constant flow conditions were studied by computational simulation. Results The implantation of BMHV could seriously interfere with the aortic rotational flow, affecting the structure and helicity distributions of the rotational flow in ascending aorta, thus resulting in disturbed blood flows distal to the valve. The 135° implantation angle caused the most disruption to the swirling flow, leading to the largest areas of reversed rotational flows, while the 0° and 45° implantation angles caused relatively smaller damage to the swirling flow. The areas with low wall shear stress (<0.5 Pa) were the smallest when the implantation angle of BMHV was 0°. Conclusions At the implantation angle of 0°–45°, the disruption of BMHV to the swirling flow in ascending aorta was relatively small. Therefore, for different patients, the selection of implantation angle should be individualized according to the spatial geometry of their aorta (including the aortic sinuses), and the implantation angle can be determined between 0°–45°.