Abstract: A method for treating an aneurysm with at least one branch blood vessel branched from a diseased aorta comprises implanting an aortic stent graft and an auxiliary stent into a diseased blood vessel to isolate the aneurysm, wherein the auxiliary stent comprises a bifurcated stent graft, one end of the aortic stent graft is attached to the wall of a healthy blood vessel upstream of the aneurysm, and the auxiliary stent comprises a body portion and a branch portion communicated with the body portion, one end of the body portion is communicated with a healthy blood vessel downstream of the aneurysm, the other end of the body portion is communicated with the aortic stent graft, and the branch portion is suspended within the diseased blood vessel. A straight stent graft is advanced towards the branch portion from the location downstream of the bifurcated stent graft and deployed to communicate the branch portion and the branch blood vessel.