Aim To observe the influence of urantide on the expression of C-reactive protein(CRP) in rats with atherosclerosis and investigate its mechanism. Methods Model with atherosclerosis was induced by feeding high fat diet and arterial intimal injury of intraperitoneal injection of vitamin D3,rats were randomly divided into four groups: control group,model group,fluvastatin group and urantide group,and the expression of C-reactive protein in aortic wall were detected by immunological histochemical method.Cultured vascular smooth muscle cells in vitro were randomly divided into four groups: control group,urotensinⅡgroup,fluvastatin group and urantide group,and the expression of C-reactive protein in supernanant were detected by enzyme-linked immunosorbent assay(ELISA). Results In the plaques of thoracic aorta intima and tunica media,the expression of the positive particles of C-reactive protein in the model group was increasing obviously compared with that in the control group and the C-reactive protein expression in each experiment group of urantide was decreasing by fluvastatin.The C-reactive protein expression in the vascular smooth muscle cells supernatant of each urantide concentration group had downward trend,among which the 10-6 mol/L urantide was decreasing most(P<0.01).Conclusions UrotensinⅡ can facilitate the over-expression of C-reactive protein in atherosclerosis.However,the promotion can be inhibited by urotensinⅡ receptor antagonist urantide.The experiment provides new views and experiment basis for the clinic treatment of atherosclerosis with urantide.