Objective To investigate the effect of simvastatin combined with mechanical stretch on osteogenic differentiation of bone marrow mesenchymal stem cells（BMSCs）and explore its mechanisms. Methods simvastatin group，mechanical stretch group and simvastatin+mechanical stretch group in the study. ALP activity and RT ⁃ PCR were used to investigate the effect of simvastatin，mechanical stretch and simvastatin + mechanical stretch on osteogenic differentiation of BMSCs and RT⁃PCR and WB were used to investigate the expression of β ⁃catenin in each group. Results The level of osteogenic relative genes was up⁃regulated and the expression of β ⁃catenin protein was increased in each group when compared with those in the control group，especially in simvastatin+mechanical stretch group. DKK1 partly eliminated osteogenic differentiation of BMSCs in simvastatin+ mechanical stretch group. Conclusion Both simvastatin and mechanical stretch promote the osteogenic differentia⁃ tion of BMSCs. Simvastatin promotes the osteogenic differentiation of BMSCs induced by mechanical stretch via