Objective: To establish a rat model of abdominal aortic aneurysm (AAA) that has high success rate and consistent with the pathological features of human AAA. Methods: Twenty SD rats were randomized into model group and control group. Rats in model group underwent pressurized infusion of porcine pancreatic elastase into a segment of the infrarenal aorta via catheterization of the left common iliac artery (a series of improvements were made during operation), while rats in control group were infused with normal saline in the same fashion. The size of the infused abdominal aortic segments of the two groups was measured by color ultrasound before and at 7 and 14 d after operation, and samples of the infused abdominal aortic segments were also obtained at 14 d after operation for elastic fiber staining. Results: The ultrasonic examination showed that the size of the infused abdominal aortic segments in control group had no obvious change at 7 and 14 d after operation, but was greatly increased in model group, and the success rate of model construction was 100%. On 14 d after operation, the cross-sectional area was (5.17±0.61)- and (1.03±0.09)-fold of that before operation in model group and control group, respectively, and the difference between the two groups had statistical significance (P<0.001). The results of elastic fiber staining showed that the elastic tissues in the media of the infused artery were severely damaged, and relative content of arterial elastic fibers in model group was significantly lower than that in control group (P<0.001). Conclusion: Through improved procedures, a rat model with high success rate and typical pathological characteristics of AAA has been well established, which may provide an ideal experimental model for basic research of AAA.