It is known that the non-planar model of bypass is more profitable to suppress the development of intimal hyperplasia that tends to occur preferentially in regions of low time averaged shear stress and rapid temporal changes in wall shear stress. In this study it was numerically simulated the blood flow in an coronary artery grafted by artificial bypass to determine the flow characteristic variations due to the anastomosis angle changing. 5 different non-planar anastomosis angle models such as 45°, 60°, 90°, 120° and 135° were considered. When the anastomosis angle is higher, the backward flow region is spatially extended near the downstream region of the anastomosis because of the development of horseshoes vortex. For the case of the nan-planar 45° and 60° of anastomosis, the area of low-OSI zone was decreased by 26% and 13% respectively and the time averaged wall shear stress was increased by more than 55% as compared with 45° of planar model. However, both of the area of the low-OSI zone and the time averaged wall shear stress of 90°, 120° model were significantly increased.