Background:　This　study　is　to　investigate　the　influence　of　hemodynamics　on　Stanford　type-A　aortic　dissection　with　different　tear　size　and　location,　to　provide　some　support　for　the　relationships　between　the　risks　(rupture,　reverse　tearing　and　further　tearing)　and　tear　size　and　location　for　clinical　treatment.　Methods:　Four　numerical　models　of　Stanford　type-A　aortic　dissection　were　established,　with　different　size　and　location　of　the　tears.　The　ratio　of　the　area　between　the　entry　and　re-entry　tears(RA)　is　various　within　the　model;　while,　the　size　and　the　location　of　the　re-entry　in　the　distal　descending　aorta　are　fixed.　In　model　A11　and　A21,　the　entry　tears　are　located　near　the　ascending　aorta.　The　RA　in　these　models　are　1　and　2,　respectively;　In　the　model　B11　and　B21,　the　entry　tears　are　located　near　the　proximal　descending　aorta　and　the　RA　in　these　models　are　again　assigned　to　1　and　2,　respectively.　Then　hemodynamics　in　these　models　was　solved　with　numerically　and　the　flow　patterns　and　loading　distributions　were　investigated.　Results:　The　flow　velocity　of　the　true　lumen　in　model　A21,　B21　is　lower　than　that　in　A11,　B11,　respectively;　the　time-　averaged　wall　shear　stress　(TAWSS)　of　the　false　lumen　in　model　A21　and　B21　is　higher,　and　for　ascending　aorta　false　lumen,　A11,　A21　are　higher　than　B11,　B21,　respectively.　False　lumen　intimal　wall　pressure　of　A11,　A21　are　always　higher　than　the　true　lumen　ones.　Conclusion:　The　variation　of　the　RA　can　significantly　affect　the　dynamics　of　blood　within　the　aortic　dissection.　When　the　entry　tear　size　is　larger　than　the　re-entry　tear　ones,　the　false　lumen,　proximal　descending　aorta　and　the　wall　near　re-entry　tear　are　prone　to　cracking.　Entry　tear　location　can　significantly　alter　the　hemodynamics　of　aortic　dissection　as　well.　When　entry　tear　location　is　closer　to　proximal　ascending　aorta,　false　lumen　continues　to　expand　and　compress　the　true　lumen　resulting　in　the　true　lumen　reduction.　For　proximal　ascending　aorta,　high　pressure　in　false　lumen　predicts　a　higher　risk　of　reverse　tear.