Coronary artery bypass grafting, the major treatment for coronary stenosis, has long-term patency problem due to intimal hyperplasia along the graft and at the graft/artery junction (proximal and distal anastomoses). It is well demonstrated that the hemodynamic factors are linked to the development of intimal hyperplasia and have been hypothesized as a cause of bypass graft failure. Although some researchers had investigated distal anastomosis, further studies upon the proximal anastomosis and even the complete bypass model, including both proximal and distal anastomoses, are still lacking in the literature and it is important and necessary for a better understanding of CABG. Therefore in this project, flow characteristics and hemodynamic parameters (HPs) distributions of proximal anastomosis and the whole bypass model were studied in order to enhance the understanding of the stenosis pathophysiological process and provide useful information for sleeve design and medical doctors. Furthermore, geometrical improvement to the distal anastomosis was proposed to reduce the nonuniformity of hemodynamics and the hemodynamic performance was evaluated and compared with a baseline distal anastomosis model. At the first stage, the effects of proximal anastomotic angle on local hemodynamics were studied to provide useful information for medical doctors and serve as the basis for the design of a whole anastomosis model, with emphasis on identifying site-specific hemodynamic features that could reasonably be expected in triggering the initiation and further development of anastomotic intimal hyperplasia. PIV measurements revealed that the flow fields in the proximal anastomosis were strongly influenced by the anastomotic angle. A large size of flow separation region was found along the graft inner wall just