Aim To investigate the protective effect of Astragali radix extract on vascular cell adhesion molecule-1 expression of mice vascular endothelial cell against tumor necrosis factor-α(TNF-α). Methods Adhesion model was established by THP-1 cells and mice endothelial cell in vitro.The cells were pretreated by different dose and different time of Astragali radix extract before induced by TNF-α,and the adhesion rate were detected.The levels of vascular endothelial cell adhesion molecule VCAM-1 in the cell culture were determined with ELISA.The expression of VCAM-1 and NF-κB subunit(p65) were evaluated by Western blot. Results The expression of VCAM-1 and NF-κB was increased obviously after induced by TNF-α;While the expression of VCAM-1 and the effect of NF-κB p65 protein nuclear translocation induced by TNF-α were inhibited after pretreatment of Astragali radix extract in a dose-and time-dependent manner.The reduction of adhension of monocytes to endothelial cells,the down-regulation of the expression of VCAM-1 and reduc-tion of the expression of NF-κB were apparent(P<0.05) at the concentration of 120 mg/L preincubated 4～8 h. Conclusion Astragali radix extract can inhibit the TNF-α-induced expression of VCAM-1 and reduce the adhension of monocytes,by which the damage to vascular endothelial cells was relieved.The mechanism may be related to the role of inhibiting the activation of NF-κB.