Objective To reconstruct a three-dimensional model of the human thoracic aorta, so as to numerically simulate and study the pulsating blood flow in human thoracic aorta. Methods A three-dimensional reconstruction of the human thoracic aorta arch was obtained using CT scan imaging on a human aorta by Mimics, a software for image processing. The numerical simulations were obtained based on the principle of computational fluid mechanics and hemodynamics. Results The distribution of velocity, pressure, and path of the blood flow in the aortic arch of normal people were calculated at a given pulsating and parabolic initial cycle. Our numerical results demonstrated that the blood velocity of distal end was greatly faster than that of proximal end on the interface between branch and aortic arch. There was an obvious pressure gradient between the inner wall and outer wall of blood vessels. The areas where the blood velocity and pressure changed greatly were consistent with the location of the thoracic aortic dissection, especially the area 2-3 cm below the left subclavian artery, suggesting that the blood pressure and velocity may greatly influence the progress of aortic dissection. Conclusion Numerical simulation and modeling based on CT scan data can help to study bio-fluid mechanics. At the same time, the numerical simulation of blood flow will greatly help the diagnosis and treatment of the aortic dissection and arteriosclerosis.