Small-diameter vascular grafts are in large demand for coronary and peripheral bypass procedures, but present products still fail in long-term clinical application. Hence, A new type of small-diameter vascular graft(SDVG) is designed with a spiral flow guider to induce spiral blood flow and thus improve the local hemodynamic performance. In present article, to investigated how the spiral flow guider influenced the hemodynam ic performance of this new SDVG, via computational fluid dynamics(CFD). The numerical results demonstrate that: 1) the spiral flow guider could indeed make the blood flow rotate; 2) the blood velocity near the vessel wall and wall shear rate(WSR) w ere greatly enhanced; 3) the number of the helical turns had obvious non-positive correlation with the hemodynamic performan ce of the new graft. It is believed that the increased blood velocity near the wall and the WSR are conductive to anti-throm bosis and anti-hyperplasia, hence the graft patency rate for long-term clinical use can be improved. Present study may also h elp better understand the optimal design of the spiral flow guider for the purpose of prolonging the long-term patency rate of th e SDVG. Small-diameter vascular grafts are in large demand for coronary and peripheral bypass procedures, but present products still fail in long-term clinical application. Therefore, A new type of small-diameter vascular graft (SDVG) is designed with a spiral flow guider to induce spiral blood flow and thus improve the local hemodynamic performance. In present article, to investigate how the spiral flow guider influenced the hemodynam ic performance of this new SDVG, via computational fluid dynamics (CFD). The numerical results demonstrate that: 1) the spiral flow guider could indeed make the blood flow rotate; 2) the blood velocity near the vessel wall and wall shear rate (WSR) w ere greatly enhanced; 3) the number of the helical turns had obvious non-positive correlation with the hemodynamic performan ce of the new graft. It is believed that the increased blood velocity near the wall and the WSR are conductive to anti-throm bosis and anti-hyperplasia, hence the graft patency rate for long-term cl inical use can be improved. Present study may also h elp better understand the optimal design of the spiral flow guider for the purpose of prolonging the long-term patency rate of th e SDVG.