Abstract: Objective To investigate the possibility of constructing small diameter vessel by means of tissue engineering in vivo. Methods Bone marrow stem cells (BMSCs)were cultured in vitro, and differentiated into vascular smooth muscle-like cells and vascular endothelium-like cells by DMEM-LG culture fluid including all trans-retinoic acid (AT-RA), dibutyryl cyclic adenosine mono-phosphate (db-cAMP) and culture fluid including vascular endothelial growth factor(VEGF) respectively. β actin and vWF expression were observed using immunofluorescence. Ultrastructural change was observed by electron microscope. The mixture of seed cells and scaffold were produced by separaely seeding vascular smooth muscle-like cells and vascular endothelium-like cells derived from BMSCs on polyglycolic acid ( PGA )/collagen scaffold. The two layers were separated by extracellular matrix gel ( ECMgel ). The tissue engineering blood vessels were examined by pressure experiment and both gross and histology with HE staining and immunofluorescence. Results BMSCs could be differentiated into vascular smooth muscle-like cells and vascular endothelium-like cells by inducing for 14 days. β actin and vWF expression were positive. Ultrastructural related changes were observed by electron microscope respectively. Histological analysis of the tissue engineering blood vessel wall revealed a typical artery structure, including endothelium, media and adventitia. Blood vessel intracavitary pressure was 100-150 mm Hg( 1mm Hg =0.133 kPa) in scaffold group, 200 mm Hg in experimental group and tissue engineering blood vessel did not break. Eight weeks after implantation, the labeled seed cells by 5- bromo-2-deoxyuridine ( Brdu ) were found in the three layers of the vessel wall. Conclusions The subcutaneous tissue is a good bioreactor to construct tissue engineering blood vessels. Histology of tissue engineering blood vessels is similar to natural vessel.