Aim:The present study was designed to evaluate the effect of umbilical cord derived mesenchymal stem cells (UC-MSCs) transplantation on traumatic brain injury (TBI). TBI remains as a serious public health problem. UC-MSCs exhibit particular characteristics of strong proliferation, low immunogenicity, and multi-potential differentiation, all of which contribute to the success of cell transplantation.Material and Methods:UC-MSCs were isolated from human umbilical cord and TBI rat model was constructed. 30 male SD rats were randomly divided into 3 groups: control group, TBI group and MSCs transplantation group. Rats in MSCs group received the injection of a total of 1.5 × 106 MSCs (25 ?l) via ventricle at operated ventricular coordinates (0 at bregma, 1.5 mm at lateral, 1.1 mm at behind, 4.5 mm in depth).Results:80% confluence of cells was formed from tissue at day 10 and the amount of CD90, CD73, CD105 positive cells increased correspondingly. In TBI model, clear hyperemia, edema and obvious infiltration of inflammatory cells in brain tissue were found. However, the manifestations were alleviated after the treatment of MSCs. In MSCs group, GFP in the brain tissue and the area around the vessels were found after the injection, while the expression levels of micro-vessel density (MVD), brain-derived neurotrophic factor (BDNF) and glial fibrillary acidic protein (GFAP) were elevated. Conclusion:UC-MSCs transplantation for treatment of acute TBI could effectively reduce the injury and improve the vascular reconstruction.