Abstract: Objective To induce the differentiation of bone marrow stromall cells (BMSCs) isolated from Beagles into osteoblasts in vitro and identify the osteogenic potential and bioactivity of the BMSCs. Methods Primary cultured BMSCs isolated from Beagles were subcultured in mineralization medium to induce their differentiation into osteoblasts, whose morphological characteristics and proliferation status were observed by phase-contrast microscope. The osteogenic activity of the cells was evaluated with von Kossa staining of the mineralized nodules and determination of the alkaline phosphatase activity. Result BMSCs cultured in vitro showed obvious osteogenic capacity in DMEM. Von Kossa staining of the mineralized nodules and alkaline phosphatase detection of the passaged cells both yielded positive results. Conclusion BMSCs cultured in vitro contain osteogenic precursor cells, and the passaged cells possess osteogenic potential.