Abstract: Objective： To investigate the effect of miR-34a on osteogenic differentiation of hOBMSCs. Methods： Real-time quantitative RT-PCR was used to detect the expression of miR-34a/miR-34b/miR-34c in hOBMSCs during osteogenic induction. The effect of miR-34a on osteogenic differentiation of hOBMSCs were detected by alkaline phosphatase staining and alizarin red staining. The regulation role of miR-34a on the expression of osteogenic markers (RUNX2, OSX, OPN, OCN, COL1A1) during osteogenic induction and the effect of miR-34a on DKK1 protein expression under normal cell culture conditions were detected by westernblot. The target relationship of miR-34a and DKK1 was measured by dual luciferase reporter assay. The effect of miR-34a on osteogenesis of hOBMSCs was examined by subcutaneous osteogenesis in nude mice. Results： MiR-34a was demonstrated to be upregulated during the osteogenic differentiation of hOBMSCs. Overexpression of miR-34a significantly increased alkaline phosphatase activity, mineralization capacity, and the expression of osteogenesis-associated genes in hOBMSCs in vitro. Further investigations revealed that miR-34a inhibited the expression of DKK1 and reduced the luciferase activity of reporter gene construct comprising putative miR-34a binding sites in the 3′-UTR of DKK1. In vivo experiments also confirmed that miR-34a can promote osteogenic differentiation of hOBMSCs. Conclusions： MiR-34a promoted hOBNSCs osteogenic differentiation via down-regulating the expression of DKK1.