Objective To determine the effect of valsartan(val) on the migration of isolated rat vascular smooth muscle cell(VSMC) and the expression of phospho-42/44 mitogen-activated protein kinase(p42/44 MAPK)promoted by angiotensinⅡ.Methods VSMC from the rat thoracic aorta was cultured by attachment-block culture.VSMC migration was measured by migration chamber system.p42/44 MAPK expression was determined by Western blot.Results(1)AngiotensinⅡobviously promoted VSMC migration,the effect was inhibited by valsartan and PD98059.(2)Angiotensin Ⅱ obviously promoted p42/44 MAPK expression,and the expression was at maximal in 5 min,the effect was inhibited by val and PD98059.(3)Compared with the control,val didn’t inhibit VSMC migration and p42/44 MAPK expression.Conclusion The effect that val inbibits angiotensin Ⅱ-induced VSMC migration is related to its inbibiting angiotensin Ⅱ-induced p42/44 MAPK expression.