Objective To observe the effects of soybean isoflavone in attenuating trans fatty acids-induced athero-sclerosis in rats .Methods The rats were randomly divided into normal diet group、trans fatty acids group、soybean isoflavone group and trans fatty acids +soybean isoflavone group .Research kit was used to test the amounts of TG , HDL,LDL and IL-6,TNF-αin rats'blood.Bovine aortic endothelial cells were cultured and divided into control group,trans fatty acids group and trans fatty acids group +soybean isoflavone group .Western blot was performed to test the NF-κB phosphorylation ,as well as to determine ICAM-1 and VCAM-1 protein contents in bovine aortic endo-thelial cells.Results Compared with normal diet group ,the amounts of TG,LDL,IL-6,TNF-αincreased evidently (P<0.05), whereas the amounts of HDL decreased evidently (P<0.05) in the rats'blood of trans fatty acids group . After the soybean isoflavone intervened ,the amounts of TG,LDL,IL-6,TNF-αall decreased (P<0.01), meanwhile the amounts of HDL increased significantly (P<0.01).Soybean isoflavone inhibited NF-κB phosphorylation induced by trans fatty acids ( P<0.01) .The high expression of ICAM-1 and VCAM-1 induced by trans fatty acids was de-creased by soybean isoflavone when comparing with those in the control group ( P<0.01 ) .Conclusions Soybean isoflavone has a role in attenuating trans fatty acids trans fatty acids-induced atherosclerosis in rats .