Previous　numerical　studies　based　on　2D　coronary　artery　bypass　graft　(CABG)　model　for　the　optimization　of　anastomosis　configuration　has　indicated　that　large　graft-host　diameter　ratio　and　small　junction　angle　has　better　hemodynamics.　The　validity　of　representing　a　3D　CABG　model　with　a　2D　CABG　model　is　not　clear.　Four　different　3D　CABG　models　and　one　2D　CABG　model　were　constructed,　and　their　hemodynamics　were　analyzed　and　compared　in　the　present　study　in　order　to　verify　this　validity.　Hemodynamics　of　the　five　CABG　models　were　numerically　simulated　using　commercial　software　ANSYS　9.0.　The　results　showed　that　the　distribution　of　flow　patterns,　wall　shear　stresses　and　wall　shear　stress　gradients　in　the　2D　model　and　3D　models　were　not　significantly　different.　Large　or　same　diameter　of　graft　compared　with　that　of　the　parent　artery,　and　small　suture　angle　is　profitable　in　clinical　application　from　the　point　of　view　of　hemodynamics.　It　can　be　concluded　that　the　conclusions　drawn　from　the　optimization　of　2D　CABG　model　is　credible　and　can　be　used　for　reference;　it　is　feasible　to　simplify　a　3D　CABG　model　to　a　2D　model　for　hemodynamics　analysis.　©2010　IEEE.