The tensile force acting on the suture line connecting a synthetic graft to a host artery in end-to-side anastomosis is shown to increase as the ratio of the graft-artery area,and has minimum value at 0.3 of the ratio of the flow rates.The angle of the end-to-side anastomosis is shown to have little effect on the suture line stress,but can not be negligated.Considering suture material and other factors,sufficient sutures per cm should be established.