Aim To investigate the effects of exenatide on the development of aortic atherosclerotic lesions in diabetes ApoE^－/－ mice. Methods The male ApoE^－/－ mice were randomly divided into three groups: control group, diabetes group and exenatide group, all fed with high-fat diet. Diabetes group and exenatide group were injected with streptozocin （STZ） intraperitoneally to induce diabetes then infused with either placebo or exenatide for six weeks. At last their body weight, heart weight, blood glucose and serum lipids were measured. And the aortic atherosclerotic plaque area, plaque composition and plaque stability score were analyzed by using HE staining and immunohistochemistry. Meantime, the protein expression levels of poly（ADP-ribose）polymerase-1（PARP-1） and induced nitric oxide synthase （iNOS） were measured by Western Blot. Results Compared with control group, the diabetes group exhibited higher serum total cholesterol, triglycerides, blood glucose, aortic atherosclerotic plaque area and lower plaque stability score, and the expression of PARP-1 and iNOS increased. While compared with the diabetes group, the exenatide group exhibited lower serum total cholesterol, triglycerides, aortic atherosclerotic plaque area and higher plaque stability score, and the expression of PARP-1 and iNOS decreased. Conclusion Exenatide can suppress the area of aortic atherosclerotic lesions and stabilize the aortic atherosclerotic plaques through PARP-1 pathway in diabetes ApoE^－/－ mice.