Objective In order to make further investigation of the functional meaning of Ca2+dependent phospholipids binding protein AnnexinⅡ, we tested the effects of AnnexinⅡ combined with embryonic neural stem cells (NSCs) transplantion on the repair of spinal cord injury (SCI). Methods The spinal cord of the adult rats was transected completely between T9T10. AnnexinⅡ and NSCs were injected at the transected site. The lesion area of the spinal cord, growth of axon, and survival number and migration of the transplanted NSCs were measured. The survival number was shown by prelabeling the NSCs with Hoechest 33342 and the growth of axon traversing the transected area was shown by fluorogold (FG) retrograde tracing. The AnnexinⅡ injection+NSCs implantation groups were compared with groups that respectively received 1. NSCs implantation alone; 2. shamoperation+NSCs implantation and 3. Vehicle injection of culture medium. Results Our results demonstrated that AnnexinⅡ treatment in vivo could significantly reduce the lesion area (P<001), increase the number of FG retrogradelylabeled neurons rostral to the injury (P<001), and improve the