Objective To investigate the protective effects and possible mechanisms of polydatin(PD) on hypoxic-ischemia brain damage(HIBD) in neonatal rat by means of the expression of intercellular cell adhesion molecule( ICAM)-1 in cortex. Methods Fifty-four SD rats were divided into 3 groups at random, shame group (no HIBD), HIBD group (no medication) ,and PD treatment group. 7day-old rat's HIBD model was established by Rice's method. ICAM-1 expression in brain after HIBD was measured in different time by Immunohistochemitry technique. Results In sham group, there were less brain microvessel immunostained positively. In HIBD group,the number of ICAM-1 immuno-positive staining blood vessels increased significantly after 6h, 12h reached peak point. ICAM-1 immunoreactive staining of blood vessels levels continued in the peak after 24h. In PD treatment group, ICAM-1 expression on brain microvascular endothelial decreased after HIBD 6h, 12h, 24h, which was significant compared with HIBD group( P < 0. 05 or P < 0. 01 separately). Conclusion The expression of ICAM-1 was involved in the procedure induced by hypoxic-ischemia. After HIBD, polydatin would downregulate ICAM-1 expression in cerebral microvascular endothelial, and inhibite the inflammatory response.