According to the range of aneurysm involvement, Ahn and Blum proposed different typing methods according to the length of proximal neck of AAA and the range of distal involvement of the aneurysm, respectively, and Thurnher proposed Siegfried’s typing according to the relationship between AAA and renal artery. In 1995, Schumacher et al. classified AAA into three main types according to the influence of aneurysm morphology and aneurysm body on clinical decision-making, of which type II was divided into type IIA, type IIB and type IIC according to the different branches involved in AAA. Type I: proximal aneurysm neck length ≥1, 5 cm, distal aneurysm neck length ≥1, 0 cm; Type IIA: proximal aneurysm neck length ≥1, 5 cm, AAA involvement of the aortic bifurcation; Type IIB: proximal aneurysm neck length ≥1, 5 cm, distal AAA involvement of the common iliac artery; Type IIC: proximal aneurysm neck length ≥1, 5 cm, AAA involvement of the common iliac artery bifurcation in the distal part of the AAA; Type III: proximal aneurysm neck length <1, In addition to this classification, the study also pointed out that type I AAA patients were suitable for straight stenting; type II patients could be repaired with "Y" stenting, and type IIC patients needed to reconstruct one side of the internal iliac artery to provide blood supply to the pelvic organs and gluteal muscles at the same time as endovascular repair; type III patients were suitable for straight stenting due to the distance of the AAA from the renal artery; type III patients were suitable for straight stenting because the AAA was far from the renal artery. Type III patients are contraindications to endovascular luminal repair because the AAA is a short distance from the renal artery and the stent vessel will affect the renal artery blood supply. In 1997, Ahn et al. classified AAA into four types according to the clinical needs of endovascular treatment, among which, type II was divided into type IIA and type IIB according to the different branches involved in AAA. Type I: proximal aneurysm neck length ≥1,5 cm, distal aneurysm neck length ≥1,0 cm; Type IIA: proximal aneurysm neck length ≥1,5 cm, distal aneurysm neck length <1,0 cm, aneurysm body does not significantly involve the common iliac artery; Type IIB: proximal aneurysm neck length ≥1,5 cm, aneurysm body distal to the common iliac artery is involved in or connected to; Type III: proximal aneurysm neck length <1,5 cm, distal aneurysm neck length ≥1, 0cm; Type IV: proximal tumor neck length <1,5cm, distal tumor neck length <1,0cm, and the tumor does not obviously involve the common iliac artery. Among them, patients with type I AAA are suitable for straight stent vascularization; patients with type IIA and IIB can be repaired with "Y" stent vascularization; and type III and IV AAA are contraindications to endoluminal treatment. In addition, due to the transverse expansion of AAA along the abdominal aorta, it is easy to cause the neck of the tumor and the tumor body to be twisted into an angle, Ahn et al. according to the degree of twisting of the proximal neck of the AAA is divided into three levels (with the straight line of the aorta without twisting as 180 °): Grade Ⅰ: the angle of the proximal neck of the AAA ranges from 150 ° to 180 °; Grade Ⅱ: the angle of the proximal neck of the AAA ranges from 120 ° to 150 °; Grade Ⅲ: the angle of the proximal neck of the AAA is less than 120 °. Grade III: AAA proximal tumor neck angulation is less than 120°. The AAA classification has important reference value in endoluminal repair. Blum classification: Type A: AAA distal and proximal aneurysm neck length >10mm, aneurysm diameter <25mm, no involvement of the common iliac artery; Type B: AAA proximal aneurysm neck length >10mm, aneurysm diameter <25mm, one side of the common iliac artery internal diameter <12mm, the aneurysm involved the aortic branches; Type C: AAA proximal aneurysm neck length >10mm, aneurysm diameter <25mm, aneurysm involved the common iliac artery and branches, and the common iliac artery and branches, and the aneurysm involved the common iliac artery and branches. Type C: AAA proximal neck length ＞10mm, tumor diameter ＜25mm, aneurysm involving common iliac artery and branches, and diameter of iliac artery branches ＜12mm; Type D: AAA involving bilateral internal iliac arteries; Type E: AAA proximal neck length ＜10mm, tumor diameter ≥25mm. Siegfried stagingThurnher put forward Siegfried staging, and this staging method is more widely used in open surgery at present. Suprarenal type: AAA involves the opening of renal artery or above; renal type: AAA is located below the renal artery within 15mm; infrarenal type: AAA is located below the renal artery more than 15mm.