To enrich our understanding of endovascular treatment of cerebral aneurysm in the era of flow diverters (FD), related literature dealing with fluid dynamic engineering is reviewed and elaborated on here.The intra-aneurysmal flow patterns could be classified into shear-driven flow and inertia-driven flow. The flow reduction effects of FD are better anticipated among aneurysms with a shear-driven flow pattern.The FDs with lower porosity reduce more blood flow into aneurysms. Under certain porosity, FDs with thinner filaments reduce more blood flow.The flow reductions of side-branches after FD are estimated as less than 20% by computer simulation. Thus, other factors such as anti-platelet drugs and neo-intimal hyperplasia may also be involved in the ischemic complications in the territory of side-branch after FD placement.Pulsatility of blood flow, which is considerably decreased in the parent artery downstream to large aneurysms, recovers shortly after FD deployment and the peak systolic velocity becomes higher after FD. The peripheral brain circulation might be changed after FD deployment in cases of large aneurysms.Blood flow simulation for FD is not easy but it would provide useful information for selecting the proper cases for FD as well as selecting the proper devices for a certain case.