Objective To investigate the effect on aneurysmal pressure after stent intervention treatment for aneurysm accompanied by stenosis. Methods Computational fluid dynamics (CFD) analyses were carried out to make comparative study on aneurysm models with and without stenosis. Three models (M1, M2, M3) were constructed to compare the pressure variations. M1 was the aneurysm model with no stenosis and no stent, M2 was forming from M1 model with a preaneurysm stenosis, and M3 was the M2 model with stent implantation at the place of the aneurysm. Results For comparison between M2 and M1, pressure increase in the aneurismal sac caused by a mild stenosis (50%) was about 1.399 9 kPa(10.3 mmHg) with the peak systole, and the average pressure increase in a cardiac cycle was about 0.572 kPa(4.3 mmHg). For comparison between M2 and M3, pressure increase in the aneurismal sac was about 1.037 kPa(7.8 mmHg) at peak systole in a cardiac cycle, and the average pressure increase in the aneurismal sac in a cardiac cycle was about 0.399 kPa(3 mmHg). Conclusions A mild stenosis could not result in the sharp pressure increase with stent intervention applied to the treatment of aneurysm accompanied by stenosis harbored on a tortuous intracranial artery. The geometry of the parent vessel and its aneurysmal/stenotic diseases do have influence on the pressure variation at the place of aneurysm.