It　is　well-established　that　blood　viscosity　plays　a　significant　role　in　the　determination　of　the　health　of　the　individual.　It　has　been　reported　that　many　cardiovascular　diseases　are　associated　with　blood　viscosity.　In　this　paper,　the　dynamic　behaviors　of　aortic　aneurysm　subject　to　physiological　blood　flow　with　normal　and　high　viscosities　are　presented.　Fluid-structure　interaction　(FSI)　method　was　used　in　the　computational　simulation.　The　influence　of　blood　viscosity　on　flow　dynamics　within　the　aneurysm　sac,　aneurismal　diameter,　cross　sectional　shape,　wall　axial　displacement　and　wall　shear　stress　(WSS)　was　studied　in　detail.　This　investigation　uncovered　the　correlations　between　blood　viscosity　and　the　dynamic　behaviors　of　aortic　aneurysm,　which　have　rarely　been　found　in　existing　literatures.　We　believe　that　these　findings　may　provide　important　implications　for　individualized　endovascular　treatment　for　patient　with　aortic　aneurysm.　(C)　2011　Elsevier　Ltd.　All　rights　reserved.