The rupture of an aneurysm can lead to a subarachnoid hemorrhage, which can be fatal in a large percentage of cases. In treating aneurysms, intravascular stenting is thought as a better option compared with clipping treatment. The treatment of cerebral aneurysm with a porous stent also has recently been proposed as a minimally invasive way to prevent rupture and favor coagulation mechanism inside the aneurysm. Flow characteristics in a box-typed straight rigid silicone with a sphere attached to the center of a baseline straight tube have been investigated using particle image velocimetry (PIV) at Reynolds number of 300. A 20 mm long mesh-work of rhombus shape stent was tested in the present investigation. Four stent porosities of 100%, 80%, 74%, and 64% were examined. Reduced velocity, smaller average vorticity magnitude and different flow patterns inside the aneurysm are observed when the three different proposed stents are used. The lower porosity stent (Porosity = 64%) decreases the magnitude of the velocity by 98% and changes the flow pattern in the aneurysm. Our results show that not only the role of the porosity but also the stent shape affects the flow. Moreover, we hope that this work will help us understand the characteristic of stent designs.