Objective To study the neuro-protective effects of magnetotherapy after traumatic brain injury of rats. Methods Traumatic brain injury models were created in 20 rats and divided randomly into magnetotherapy and non-magnetotherapy groups. The rats in magnetotherapy group received magnetotherapy on the cranial surface of traumatized region twice daily, each for 20 min, over 10 d. The intensity of magnetic field was O. 15 T at the surface,and 0.1 T during spinning at 3000 rpm. The contraction strength of gastrocnemius of each rat's left hind limb was measured on the 11 th d after trauma. The rats were then sacrificed and brain tissue samples were taken. The infiltra-tions of CD4 + and CD8 + cells and apnptosis in the area around the injury lesion were observed with immunohisto-chemical methods. The relationship among the indexes was analyzed. Results At the 11th d after brain injury, the quantities of CD4 + and CD8 + cells and apoptotic cells in magnetotherapy group were all obviously less than those in non-magnetotherapy group. Average contraction strength of gastrocnemius in magnetotherapy group was significantly stronger than that in non-magnetotherapy group. Conclusions Magnetotherapy can relieve the secondary effects of brain injury and induce neuro-protection effects. This may involve decreasing the local infiltrations of CD4 + and CD8 + and apoptotic cells in the area around the injury lesion.