Objective The key techniques for geometry reconstruction based on Magnetic Resonance Images (MRIs) was elaborated. The three-dimensional numerical simulation of blood flow in human aortic arch was performed to provide fundamentals in genesis of aortic dissection and arteriosclerosis.M ethods Digital geometry reconstruction based on the clinical Magnetic Resonance Images (MRIs) was made by using image analysis. Pulsating flow rate were imposed on the CFD model as boundary conditions and three-dimensional blood flow field in the aortic arch was numerically modeled. Results Distributions of blood velocity, pressure, wall shear stress (WSS) in the human aortic arch at different point during one cardiac circle were determined by calculation.C onclusion The key techniques used in geometry reconstruction is helpful to carry out the further more research in bio-fluid mechanics. Numerical simulation of the blood flow in the present study could play an essential role in clinic diagnosis and treatment of aortic dissection and arteriosclerosis.