Objective To investigate the feasibility of bone marrow mesenchymal stem cell (hBMSC) transplantation combined with hyaluronic acid poly-l-lysine (HA-PLL) to treat spinal cord injury. Methods hBMSC were extracted from human bone marrow and were cultured and expanded in vitro. The spinal cord of rat was hemi-transected, hBMSC, HA-PLL or hBMSC plus HA-PLL were transplanted alternatively after the injury. The motor function was assayed at different time points. Eight weeks later rats were sacrificed, the growth of axons and micro-blood vessels of different groups were checked, the therapeutic effect of cells, materials and the combination were assayed. ResultsThe progression of rat locomotor function examined by BBB score showed that both groups of hBMSC transplant and hBMSC combined with HA-PLL have better recovery than hemi-transection group and HA-PLL group. Electron microscopy showed combination of hBMSC and HA-PLL can promote axonal and vascular growth. ConclusionshBMSC can promote neurological function recovery. Combination of stem cells and HA-PLL may get better effect. Based on these results, we deduced that the mechanism included the framework supporting effect of materials, the neurotrophic and angiogenesis effect of hBMSC.