To examine the therapeutic effect of Buyang Huanwu Decoction (BYHWD) combined with bone marrow mesenchymal stem cells (BMSCs) transplantation on spinal cord injury (SCI) with Chinese medicine pattern of qi deficiency and blood stasis, and to explore its mechanism. Methods: A total of 120 male SD rats were randomly divided into the following five groups with 24 rats in each: the control, qi deficiency and blood stasis, BYHWD, BMSC, and BYHWD+BMSCs groups. SCI with qi deficiency and blood stasis rat models were established, and BYHWD, BMSC, or BYHWD+ BMSC treatment was administered for a duration of 28 days. Recovery of forelimb motor function was assessed by observing spontaneous vertical exploration before treatment and at 1, 14, and 28 days of treatment. After 28 days of treatment, we performed the ELISA test to measure cAMP concentration in the spinal cord, HE staining to observe the local axon morphology in areas of damage, and immunohistochemistry to detect the local expression of RhoA, nerve growth factor (NGF), and brain-derived neurotrophic factor (BDNF). Results: After treatment, rats in the BYHWD, BMSC, and BYHWD+BMSC groups showed greater usage rate of forelimbs and higher spinal cord concentrations of cAMP compared to the qi deficiency and blood stasis group rats (all P<0.01); furthermore, the BYHWD+BMSC group displayed greater results than the BYHWD and BMSC groups (all P<0.05 or P<0.01). HE staining revealed that, in the qi deficiency and blood stasis group and BMSC group, rubrospinal tract (RST) axons suffered edema or disappeared, and myelin sheaths became disorderly arranged. In the BYHWD and BYHWD+BMSC groups, there was a reduction in the degree of spinal cord injury. Immunohistochemistry showed that, compared with that in the qi deficiency and blood stasis group, expression of NGF and BDNF in the BYHWD and BYHWD+BMSC groups increased; expression of BDNF in the BMSC group increased and that of RhoA decreased (P<0.05 or P<0.01). Additionally, expression of BDNF was higher and that of RhoA was lower in the BYHWD+ BMSC group compared to the BYHWD and BMSC groups (P<0.05). Conclusion: BYHWD combined with BMSC transplantation can produce a synergistic effect on the protection of local axons in SCI with qi deficiency and blood stasis and on the improvement of forelimb motor function. The mechanism may be related to up-regulating cAMP concentration, inhibiting RhoA expression, and up-regulating NGF and BDNF expression in the spinal cord microenvironment.