Flow diverters (FDs) are high density meshed stents designed to reduce blood flow into intra-cranial aneurysms. Though the FD is one of many intracranial aneurysm (IA) treatments, FD implantation may also result in the growth and rupture of residual aneurysms. The purpose of this research is to investigate the effect of FD implantation on IA hemodynamics. Computational fluid dynamics (CFD) was conducted to analyze dynamic and resistance forces after FD deployment. Simulation results for the successful case (patient A) showed that FD flow resistance force was higher than dynamic force. This indicated that the FD provided sufficient resistance to reduce flow into the aneurysm. As a result, flow velocity magnitude at the aneurysm neck was reduced by 95%. On the other hand, the flow velocity magnitude at the aneurysm neck was reduced by about 50% for the unsuccessful case (patient B). The reason was that the flow resistance force at the aneurysm neck section was calculated to be lower than the flow driving force. In order to completely occlude the aneurysm, a higher resistance FD stent is to be required to suppress the dynamic forces. Patient-specific hemodynamic simulations offer means of quantitative estimation FD treatment outcomes.