Objective To investigate the effect of olmesartan medoxomil on osteoprotegerin and serum inflammatory factor expression in atherosclerosis model rat.Methods From 2015 April in Jiangsu Institute of schistosomiasis control,24 Sprague-Dawley rats were randomly divided into the following three groups:the control group was fed with standard food,the model group was fed with high fat diet based on standard food(normal food +2％ cholesterol +5％ goat fat +0.2％ acid +7×105 IU/(kg·d) Vitamin D3),and the olmesartan group was given 3 mg/(kg·d) olmesartan gavage daily on the basis of high fat diet.On the fourth week of experiment the level of serum high sensitivity C reactive protein and serum lipids include total cholesterol,low density lipoprotein,high density lipoprotein and triglyceride were detected.The structure and changes of aortic pathology was observed.The expression of osteoprotegerinin in aortic was detected by immunohistochemistry staining and Western blot.Results Within the model group,the level of serum lipid and high-sensitivity C reactive protein increased significantly,endometrial thickness,intima-to-media thickness ratio and osteoprotegerin expression in aorta was significantly higher than that of normal group,the difference was statistically significant(P<0.05).The serum high density lipoprotein increased significantly,the level of other serum lipids and high sensitive C reaction protein decreased significantly,endometrial thickness,intima-to-media thickness ratio and osteoprotegerin expression in aorta of the olmesartan treated rats were significantly lower than those of model animals,the difference was statistically significant(P<0.05).Conclusion Olmesartan may suppress the development of atherosclerosis in model rats by decreasing the expression of osteoprotegerin and the level of serum inflammatory cytokines.