Objective  To provide pathologic and anatomic basis for constructing outflow tract adopting sural arteries at the end stage of arterial sclerosis obstruction(ASO).  Methods   The red emulsion was infused into the arteries of 11 fresh upper leg specimens getting from knee amputation, after that, the pathologic changes of sural and popliteal arteries were dissected and analyzed. As well, the construction of collateral outflow tract was proposed. For 9 patients of ASO, lower extremity arteriography was undertaken, which proved that, femoral, popliteal arteries and their branches were nonvisulized, while sonography showed fundamental obstruction of those arteries. And then exploration of artery were carried out, followed by sural arteries forming and the by-pass between femoral and popliteal arteries.  Results  Anatomic dissection showed that, ① the wall of popliteal artery was rigid, with atheromatous plaque stuffing the lumens;②the opening of sural arteries appeared three types: open type, membrane obstruction type and pillar obstruction type;③the clinical symptom disappeared, skin temperature turn warm gradually，lower limb ulcer healed, and sural arteries dilated, after the operation of construction of collateral outflow tract.  Conclusions  The anatomy and clinical research proves that, the construction of collateral outflow tract adopting sural arteries is feasible.