The objective of this study was to describe imaging features and to evaluate the efficacy of flow diverter stent in treatment of complex intracranial aneuryms. Prospective and retrospective study of 37 patients harboring 38 complex intracranial aneurysms were diagnosed and treated with flow-diveter Pipeline stent at Bach Mai Hospital from 2012 to August 2014. Aneurysmal features were analysed by angiography. The degree of aneurysmal occlusion was followed up in DSA and MRA post treatment. Clinical status was evaluated using modified Rankin scale. The result showed that the rate of wide - neck aneurysm, giant aneurysm, fuzzy-form aneurysm, major recanalization aneurysm post coiling and blister-like aneurysm were 57.89 percent, 13.16 percent, 10.53 percent, 10.53 percent and 7.89 percent respectively. The successful stent deployment was 97.4 percent. On follow-up by MRI and DSA, complete occlusion occurred in 5.3 percent immediately after the intervention, 85.7 percent after 3 to 6 months, and 90.3 percent after 12 months. Good clinical status (modified Rankin scale 0 - 1) was 91.9 percent. In conclusion, flow-diverting stents represent an important tool in the treatment of complex intracranial aneurysms with satisfying result.