In　order　to　provide　a　theoretical　basis　for　the　clinical　treatment　of　thoracic　aortic　aneurysm,　a　3D　finite　element　model　of　thoracic　aortic　aneurysm　was　constructed　and　numerical　simulation　of　hemodynamics　was　performed.　Based　on　clinical　patient-specific　CT　data,　an　optimized　surface　model　of　thoracic　aortic　aneurysm　was　constructed　using　digital　image　processing　software　Mimics　11.　Then　the　surface　model　was　exported　into　ANSYS　ICEM　CFD11.0　to　generate　volume　mesh.　At　last　CFD　analysis　was　performed　using　ANSYS　CFX11.0.　Finite　element　model　of　patient-specific　thoracic　aortic　aneurysm　suitable　for　hemodynamics　simulation　was　established.　Distribution　and　changes　of　streamline,　velocity　vector,　pressure　and　wall　shear　stress　were　obtained.　Rupture　mechanism　of　thoracic　aortic　aneurysms　can　be　analyzed　based　on　patient-specific　model.　Model　with　digital　and　patient-specific　feature　can　be　applied　to　hemodynamic　analysis　of　thoracic　aortic　aneurysm.