By　means　of　Finite　Element　Method(FEM),　the　physiological　blood　flow　in　coronary　bypass　graft　is　simulated.　The　stenosis　in　coronary　artery　and　the　deformation　of　graft　end　to　allow　the　surgical　suture　with　a　smaller　diameter　cornary　were　taken　into　consideration　in　the　graft　model.　The　flow　pattern,　secondary　flow　and　wall　shear　stress　in　the　vicinity　of　anastomosis　were　analyzed.　It　is　shown　that　a　zone　of　low　wall　stress　and　high　wall　stress　gradient　exists　downstream　the　toe.　The　floor　opposed　to　the　anastomosis　is　an　area　of　high　wall　stress　and　high　wall　stress　gradient.　Both　the　toe　downstream　and　the　anastomosis　floor　are　prone　to　intimal　hyperplasia,　so　it　is　concluded　that　the　high　wall　stress　gradient　may　be　relevant　to　the　intimal　hyperplasia.