Abstract: To search the new method of treatment of Abdominal Aortic Aneurysms (AAA), wehave successfully established the animal models which are similar to human in pathogenesis by perfusing theinfrarenal abadominal aorta of SD rats with Porcine pancreatic elastase. The above models were divided intocyclosporine A (CsA) treatment group and normal saline control group. The pathological change of the aor-tic wall and the diameter of the AAA were observed. Each group had 24 rats. The results show that thegrowth of AAA and the destruction of the wall of AAA in the treatment group have been greatly limited.The pathogenesis was also discussed.