Objective To investigate the role of micro RNA-451 (miRNA-451) in promoting the osteogenesis of mesenchymal stem cells (MSCs) by targeting regulatory calcium binding protein 39 (CAB39). Methods pMIR-report and pRL-TK vectors were selected to identify the relationship between miRNA-451 and CAB39 by using dual-luciferase reporter assay. pre-miRNA-451 (group A), anti-miRNA-451 (group C), pre-miRNA negative control (group B), and anti-miRNA negative control (group D) were transfected into the C3H10T1/2 cells, respectively. Then, the cells were collected after osteogenic induction for 7 and 14 days. At 7 and 14 days, the real-time fluorescent quantitative PCR and Western blot assays were performed to detect the related osteogenetic biomarkers [Runx2 and alkaline phosphatase (ALP) mRNA] and expressions of CAB39 protein. At 14 days, the extracellular calcium deposition during the osteogenesis of MSCs was tested by Alizarin red staining method. Results CAB39 was the target gene of miRNA-451. At 7 and 14 days after osteogenic induction, the mRNA expressions of Runx2 and ALP in group A were significantly higher than those in group B (P lt; 0.05), and the expressions in group C was significantly lower than those in group D (P lt; 0.05). Furthermore, at 14 days after osteogenic induction, the protein expression of CAB39 in group A (0.55 ± 0.05) was significantly lower than that in group B (1.00 ± 0.07), and the protein expression in group C (1.21 ± 0.05) was significantly higher than that in group D (1.00 ± 0.04), all showing significant difference (P lt; 0.05). Finally, at 14 days after osteogenic induction, the extracellular calcium deposition in group A was obviously more than that in group B, and group C was downregulated when compared with group D. Conclusion miRNA-451 can promote the osteogenesis process of MSCs by downregulating the CAB39.