Rupture of cerebral aneurysms often causes subarachnoid hemorrhage which is a life-threatening condition with high mortality rates. Larger aneurysms are believed to be more likely to rupture and should therefore be treated. Recently, flow diverters (FDs) are widely used to treat large or wide neck aneurysms. However, it can be difficult to treat them by deployment of a single FD because of its insufficient flow disturbance. To overcome this problem, double stenting technique is sometimes applied with the aim to improve the effect of blood velocity reduction. In this study, we used computational fluid dynamics (CFD) to investigate the hemodynamic changes in an aneurysm when deploying virtual FDs. The results showed that the characteristics of the blood flow field inside the aneurysm did not changed much after the deployment of a single FD but underwent a large change after the deployment of two FDs. Furthermore, the velocity reduction in the aneurysm sac at a plane away from the parent artery increased from 25.9% to 92.8% when two FDs were deployed instead of one compared to no stenting. Double stenting was effective to decrease blood velocity in large or wide neck aneurysms.