Objective To study the effects of embryonic neural stem cells transplantion on trauma of red nucleus neu-rons of the rats with spinal cord injury.Methods NSCs in logarithmic phage were labeled with BrdU,a Sprague Dawley rat mode of spinal cord injury (SCI) was developed with electrocircuit control spinal cord injuring device.Thirty SD rats were randomly divided into three groups: sham group,SCI group and NSC group.The NSCs were trans-planted into injured site three days after SCI.Then NSCs labeled with Brdu were detected by immunohistochemisty,rubrospinal tract (RST) neurons were labeled by retrograde transport of the horseradish peroxidase (HRP) from the lesion site,which were taken by damaged axons and remained in the neurons,then the labeled red nucleus (RN) neurons were counted.Hind limb function of experimental rats was evaluated by a blinder observer using BBB open field locomotion rating score.Results BrdU positive NSCs were detected in the spinal cord after transplantation,the number of RST neurons labeled by HRP in NSC group was more than that in SCI group (P <0.01),the BBB score of NSC group was higher than SCI group (P <0.01).Conclusion The transplanted NSCs can survive in the injured site of spinal cord and protect RN,then promote more remarkably functional recovery after SCI.