Abstract： ObjectivePanax notoginsen saponins(PNS) is refined from Chinese traditional medicine Sanqi.Aim To investigate the curative effects of PNS by injecting on vascular endothelial function and aortic artery intima-media thickness of injured endothelium in New Zealand rabbits with hyperlipodemia. Methods The experimental model of atherosclerosis in rabbits was established by hyper-lipoidal feed with 1.5% cholesterol diet in this study.The rabbits were divided into normal control group,AS model group, medium dose PNS group(PNS 50 mg·kg-1·d-1) and high dose PNS group(PNS 100 mg·kg-1·d-1). Administration was for 12 consecutive weeks.Serum lipids,nitrous oxide(NO)、the activity of nitricoxide synthase(NOS)、plasma Endothelin (ET-1) thromboxaneB2(TXB2)、6-keto-prostaglandinF1a(6-keto-PGF1α)and morphological atherosclerosis changes were evaluated after the treatment of PNS by injecting. Results Compared to AS group ,the serum levels of ET-1、TXB2 were obviously reduced than that in AS model group(P<0.01),the serum level of NO、6-keto-PGF1α was higher(P<0.01),and the activity of NOS was higher(P<0.01) in high-medium-dose PNS group.PNS reduced the lesions of hyperlipidemia vessels,Aortic artery intima of film Thickness in high、medium dose PNS group was obviously lower than that in AS group (P<0.01) by Olympus BX5 microscope;and by electron microscope showed a lot of lipid-drop let、vacuoles in foam cells and tunica media contractile fiber intracytoplasm, even adipose capsule in AS model group;AS degree of high-medium-dose PNS group was lighter than that in AS model group,no lipid-drop let vacuoles in cytoplasm of the endothelial cells,and various cell organs and elastic membrane were seen,but few lipid drop let vacuoles in cytoplasm of medial smoothmuscle cellswere found.Conclusions The ingredients of PNS was found to protect arterial endotheliumfrom injury,and regulate the secration of endothelial cell,and this improvement appears to be related to morphologic changes.