This study investigates a feasibility for patient-specific blood flow simulation, using a set of measurement data obtained from DSA and PC-MRI with respect to a geometry and velocity. The present approach naturally satisfies the physical consistency through boundary condition. The pressure boundary values are evaluated by relaxing a misfit of velocity field between measurement and simulation based on a proportional feedback control. The investigation involves a patient-specific aneurysm model reconstructed from DSA image, where the aneurysm is developed at the bifurcation with three branches. The result shows that a difference of velocity field between the measurement of the PC-MRI and simulation is reduced to 19.8% in systole condition, and then a reasonable wall shear stress distribution can be reproduced by the use of the measurement velocity data without explicitly giving the boundary conditions. The present approach exhibits a feasibility of the simulation-based blood flow analysis for understanding patient-specific hemodynamics.