Objective:　To　investigate　the　effects　of　different　bypass　grafting　for　treating　DeBakey　Ⅲ　aortic　dissection.Methods:　The　patient-specific　models　of　DeBakey　Ⅲ　aortic　dissection　based　on　CT　images　were　reconstructed　by　using　Mimics　software,　and　two　bridge　models　of　bypassing　between　ascending　aorta　and　abdominal　aorta　(AA),　and　between　left　subclavian　artery　and　abdominal　aorta　(LA)　were　established　by　computer-aided　method,　respectively.　Then　numerical　simulations　were　performed　by　using　fluid-structure　interaction　(FSI)　method　to　compare　hemodynamic　differences　of　these　two　models.Results:　After　bypass　surgery,　the　mass　flow,　mean　and　maximum　velocities　of　the　through　lumen　models　were　reduced　to　different　degrees.　Meanwhile,　both　the　maximum　blood　pressures　and　displacements　of　the　vessel　walls　of　AA　models　were　decreased,　but　those　of　LA　models　were　increased.　In　contrast,　all　the　above-mentioned　hemodynamic　parameters　of　the　blind　lumen　models　were　decreased,　especially　for　AA　models.Conclusions:　The　AA　bypassing　is　a　better　treatment　for　DeBakey　Ⅲ　aortic　dissection　of　through　lumen　and　blind　lumen.　The　therapeutic　effects　can　be　easily　explained　through　simulation　results,　to　ensure　the　scientific　validity　and　clinical　utility　of　bypassing.　©,　2014,　Yiyong　Shengwu　Lixue/Journal　of　Medical　Biomechanics.　All　right　reserved.