Aim Certain long-chain water-soluble polymer,known as drag reducing polymer （DRP）,when added in minute concentrations,have been shown to decrease peripheral vascular resistance. In this study,the effect of DRP on the hypertension-induced aortic remodeling was evaluated in spontaneous hypertensive rat （SHR）.Methods 24 male SHR were divided into three groups 8 male,age matched Wistar rats （WR） as control. The experimental groups of SHR received an intravenous injection of normal saline （SHR＋NS group）,10 mg/L DRP （SHR＋10 mg/L DRP group）,20 mg/L DRP （SHR＋20 mg/L DRP group）,respectively. The control group only received equal-volume of normal saline （WR＋NS group）. The whole study spanned 2 months,and body weight,heart rate,systolic blood pressure were measured at the beginning and every 20 days. Then blood sample and aorta were collected. Serum endothelin （ET） was measured by enzyme-linked immunosorbent assay （ELISA）. The aorta was stained by hematoxylin-eosin （HE）,andaortic medial thickness was evaluated for each section. The expression of endothelin-1 （ET-1） of aorta was examined by immunohistochemistry.Results There was no significant difference between the SHR groups in body weight and heart rate during the treatment period. Systolic blood pressure was significantly reduced in SHR＋20 mg/L DRP group than in SHR＋NS group （P<0.05）,while there was no significant difference between SHR＋10 mg/L DRP group and SHR＋NS group. Compared with the SHR＋NS group,the levels of serum ET decreased in SHR＋10 mg/L DRP group and SHR＋20 mg/L DRP group （P<0.05）. The medial thickness of the aorta was reduced in SHR＋10 mg/L DRP group and SHR＋20 mg/L DRP group compared with SHR＋NS group. The expression of ET-1 of the aorta was significantly attenuated in SHR＋10 mg/L DRP group and SHR＋20 mg/L DRP group.Conclusions These results suggest that chronic treatment with DRP can protect against aortic remodeling in spontaneous hypertensive rats,possibly by improving blood shear stress in aorta. DRP may offer a new approach to the treatment of aortic remodeling caused by hypertension.