Aim To study the effects of vascular adventitial vascular cell adhesion molecule-1(VCAM-1) and intercellular adhesion molecule-1(ICAM-1) on atherosclerotic lesion formation. Methods Apolipoprotein E Knockout(ApoE-/-) mice and wild-type C57BL/6 black mice of 6 weeks were used in this experiment.All animals were fed hyperlipidic diet for 2,4 and 8 weeks.The ascending aorta was removed with the heart attached for serial sectioning.Some sections were stained by Movat method in order to observe the morphological changes of the tissues and measure the thickness of vascular adventitia.Some sections were stained with immunohistochemistry to observe the changes in the expression of vascular adventitial ICAM-1 and VCAM-1 at different stages. Results ApoE-/-mice of 6 weeks and C57BL/6 mice at any time point did not show any changes of adventitial thickness,nor expression of VCAM-1,nor intimal lesion formation.After hyperlipidic diet for 2 weeks in ApoE-/-mice,the adventitial thickness increased and the expression of VCAM-1 was found in the adventitia when there was no visible intimal lesion formation.After hyperlipidic diet for 4 weeks the foam cells were showed in the intima and the atherosclerotic lesion developed after hyperlipidic diet for 8 weeks in ApoE-/-mice.The adventitial thickness and the expression of VCAM-1 in adventitia and intimal lesion of ApoE-/-mice increased.The expression of ICAM-1 in the adventitia and the intima of ApoE-/-mice increased gradually with increasing duration of the hyperlipidic diet.However the expression of ICAM-1 was infrequent and stable in C57BL/6 mice. Conclusion The expression of VCAM-1 and ICAM-1 in the adventitia of ApoE-/-mice increased gradually with increasing duration of the hyperlipidic diet.