Rhesus bone marrow mesenchymal stem cells (MSCs) were transfected with the BMP12 gene by electroporation, and the phenotype of the transfected cells was identified by morphological observation and molecular biological assay. After transfection, cells became slender, and their processes became thinner and were interwoven into a network. There were more organelles in the transfected cells than in the parental MSCs. The transfected cells exhibited mRNA expressions of BMP12, collagen type I and scleraxis, but not collagen type III mRNA expression. Immuno-cytochemical analysis also showed the presence of collagen type 1, but not collagen type III in the transfected cells. The transfected cells were positive for CD44 and negative for HLA-DR. Therefore, MSCs can be introduced to differentiate into tenocytes by BMP12 gene transfection, and bone marrow MSCs can serve as an alternative seed cell for application in tendon tissue engineering.