[Objective]To investigate the expression and the mechanism of EGb after the spinal cord injury in SD rats.[Method]Spinal cord injury of the SD male rats was induced with Allen's way by a 5g?5 cm impact on the posterior T9 spinal cord in moderate degree. Rats were randomly divided into two groups. One group of rats were treated with normal saline solution, while another group were administrated EGb 0.75 ml/(kg?d). Rats were sacrificed at 1、3、5、7、14 d after the injury. The expression of iNOS was determined by immunohistochemistry.[Result]Positive expression of iNOS appeared in both groups and reached their peak on the 5th day after the injury. The expression of the EGb treated group were significantly lower than that of the control group (P