This study developed a protocol for inferring the leptomeningeal flow capacity of each individual through computer simulation and compared the results with the clinical indices. To do this, MRA image provided by the hospital was reconstructed as a 3D model and blood flow analysis was performed through the Navier-Stokes equations. Peripheral blood vessels of cerebral vessels, venous system, intracranial pressure and cerebrospinal fluid circulation were analyzed using the 0D model, and arterial pressure obtained through this analysis was applied as exit boundary conditions for 3D numerical analysis. The study findings show that the activity of the collateral circulation, as well as the degree of vessel stenosis, is a major factor in determining the pressure ratio. Therefore, the cerebral vascular reserve is dependent on collateral circulation and vascular structure in addition to vascular stenosis. This fact can be confirmed by cerebral vessel simulation developed in this study.