Abstract： Objective To investigate the potential of neural stem cells (NSCs) injected into the cistema magna to migrate into the injured brain tissue to survive and differentiate into neural cells in rats with traumatic brain injury (TBI). Methods Embryonic NSCs cultured in vitro were labeled with BrdU and identified using immunofluorescence assay for nestin and BrdU expression. The labeled NSCs were stereotactically injected into the subarachnoid spaces of rats 24 h after experimental traumatic brain injury. The motor neurological function of the rats was assessed 24 h before and 24 h and 1 and 2 weeks after the injury, and immunohistochemistry was used to detect the expressions of BrdU, MAP2 and GFAP in the brain tissues. Results Positive expressions of nestin and BrdU were detected on the neurospheres by immunofluorescence assay. NSC transplantation resulted in significantly improved motor neurological function of the rats with traumatic brain injury (P<0.05). Immtmohistochemistry demonstrated the presence of BrdU-positive NSCs, MAP2-positive neurons and GFAP-positive glial cells in the traumatic brain tissue of rats 1 and 2 weeks after NSC transplantation. Conclusion Neural stem cells injected via the subarachnoid space can migrate into the injured rat brain tissue and differentiate into neural cells to promote the recovery of motor neurological function of rats with traumatic brain injury.