The　incidence　and　mortality　of　cerebral　aneurysm　have　a　remarkable　increasing　trend　in　recent　years.　Although　there　are　numerical　investigations　focusing　on　normal　cerebral　artery　and　aneurysm,　respectively,　studies　on　the　relationship　between　the　two　models　have　rarely　been　reported.　In　order　to　compare　the　biomechanical　differences　between　cerebral　aneurysm　and　normal　cerebral　artery　considering　vessel　compliance,　fluid-structure　interaction　(FSI)　algorithm　is　employed.　Two　models　reconstructed　based　on　CT　images　using　simplified　method　are　presented.　One　model　is　normal　cerebral　arteries,　the　other　is　a　lesion　model　of　the　original　arteries　when　pathological　changes　appears,　that　is,　a　saccular　aneurysm　arises　at　the　apex　of　the　bifurcation,　and　parent　arteries　becomes　twisted.　Results　such　as　wall　motion　pattern　and　blood　flow　structure　have　been　described　and　compared.　Results　illustrates　that　the　propagations　of　displacement,　velocity　and　WSS　along　the　solid　wall　are　not　synchronous.　Vessel　compliance　plays　a　crucial　role　in　causing　the　corresponding　results.　The　present　studies　can　provide　an　innovative　idea　and　strategy　for　researches　on　pathological　change　process　from　healthy　arteries　to　abnormal　ones,　and　is　of　good　reference　value　for　medical　research　on　related　fields.　©　2010　International　Federation　for　Medical　and　Biological　Engineering.