Objective To observe the effect of Astragalus injection on endoplasmic reticulum stress during the vascular remodeling in hypertensive rats, and investigate its molecular mechanism of vascular protection. Methods Male Wistar rats were randomly divided into control group, model group and intervention group. “Abdominal aortic stenosis”methods was used to prepare the hypertensive rat model. From the second day after surgery, the rats in the intervention group were injected with Astragalus injection solution 8 g/ (kg·d)intraperitoneally. Blood pressure was measured by rat caudal artery manometry at 1, 2, 4 and 6 weeks after the operation. Then, the animals were anesthetized and the aorta was separated, and pathology and immunohistochemistry were performed to determine the thickness of vascular muscle layer using an image analysis system. The expression of CRT and caspase-12 was detected by Western blotting, and the apoptosis rate of VSMC was determined by TUNEL assay. Results In the model group, pathological changes of VSMC were observed, and blood pressure, the thickness of the artery wall muscle layer and the apoptosis rate of VSMC were increased in a time-dependent manner. CRT expression was significantly increased at 1-2 weeks after the operation, but decreased at 4-6 weeks. Caspase-12 expression was increased 2 weeks after the surgery, and the increase in expression became more significant over time. In the Astragalus intervention group, the morphology of VSMC was improved to some extent. Blood pressure, the thickness of vascular wall muscle layer and the apoptosis rate of VSMC were significantly decreased. The biggest decrease was observed at 6 weeks after Astragalus intervention. Astragalus inhibited the early high expression of CRT and the high expression of caspase-12, and this inhibitory effect became more obvious as time progressed. Conclusions Astragalus decreases hypertension in rats to some degree and improves aortic vascular remodeling. Its mechanism may be related to the regulation of ERS molecules.