This study compared three β-aminopropionitrile (BAPN) treatment rats to find the optimal BAPN model for thoracic aortic dissection and aneurysm in one study. Sixty rats were divided into five groups: control, injected control, 0.25% and 0.4% BAPN treatment (orally), and 667 mg/kg/day BAPN injection subcutaneously. Incidence of aortic dissection and aneurysm, aortic weight and diameter were measured directly. Thickness of media and area of aorta were measured by hematoxylin and eosin and Victoria blue staining. The mortality, incidence of aortic dissection and the rupture rate of dissected aneurysm in 0.25% group was much higher than in the other two BAPN treatment groups. The diameter of thoracic aorta in 0.25% and the whole aorta in 0.4% group significantly increased. Media thickness and area of thoracic aorta were increased by 91% and 54% in 0.25% group, and by 17% and 12% in the BAPN injection group. Thickness and area were increased by 49% and 35% on thoracic aorta, and 29% and 46% on abdominal aorta in 0.4% group. In conclusion, 0.25%, 0.4% and BAPN injection groups might be appropriate for aortic dissection and pharmaceutical study, thoracic-abdominal aortic aneurysm or dilation and biomechanical research, respectively.