〔Abstract〕 Objective To explore the therapeutic effect and mechanism of bone marrow mesenchymal stem cells(BMSCs) on ischemic stroke in rats. Methods BMSCs were isolated by whole bone marrow adherence method and identified by flow cytometry.The rat model of middle cerebral artery occlusion(MCAO) was established and randomly divided into sham operation group, MCAO group and BMSC group.The rats in each group were scored by mNSS and stained with TTC.Immunohistochemistry, immunofluorescence and Western blot were used to detect the positive expression levels of Caspase-3,MAP-2,GAP-43 and GFAP in the infarct area and surrounding areas of the brain tissues of each group. Results Flow cytometry detected that BMSCs expressed low CD45 and high expression of CD90 and CD29; The mNSS score and the percentage of infarct volume of rats on the 3 rd, 7 th and 14 th day after transplantation of BMSCs all decreased; The Caspase-3 in the infarct area decreased, and the expression of MAP-2,GFAP and GAP-43 increased. Conclusion BMSCs transplantation can promote the recovery of neurological function and reduce the volume of cerebral infarction in MCAO model rats, possibly through mechanisms such as nerve regeneration cell proliferation, inhibition of cell apoptosis, and axon regeneration.