Objective To explore the function and mechanisms of Wnt7a in bone msenchymal stem cells (BMSCs) osteogenic differentiation.Methods BMSCs were isolated and cultured.After transfection of siRNA-Wnt7a and mock in BMSCs and induction by osteogenic medium for 3 d,Western Blot were employed to detect the silencing effect of siRNA-Wnt7a.Then the effect of silencing Wnt7a on the expression of osteocyte marker osteocalcin and osteogenesis regulator protein Runx2 were detected by Western Blot after culture by osteogenic medium for 10 d.Finally,Alizarin S Red staining was used to detect the effect of silencing siRNA-Wnt7a on osteogenesis after culture by osteogenic medium for 2 weeks.Results The silencing effect of siRNA-Wnt7a was confirmed by Western Blot after transfection of oligocleotides siRNA-Wnt7a and mock into mesechymal stem cells.The silencing Wnt7a decreased the expression of osteocalcin and Runx2 after culture by osteogenic medium for 10 d.Alizarin S red staining results showed that silencing Wnt7a blocked bone differentiation.Conclusions The results demonstrated that Wnt7a could promot osteocyte marker osteocalcin expression by upregulating osteogenesis regulator protein Runx2 expression,which played a key role in BMSCs osteogenic differentiation.