OBJECTIVE: To investigate the effect and related mechanisms of miR-485-5p on the osteogenic differentiation of rat bone marrow mesenchymal stem cells (BMSCs). PATIENTS AND METHODS: The expression level of miR-485-5p was detected in clinical cases and during the osteogenic differentiation. Three group were established to study the potential function between miR-485-5p and osteogenic differentiation: miR-NC group (negative control), miR-485-5p mimics (BMSCs transfected by miR-485-5p mimics), and mimics + si-Osx (BMSCs transfected by miR-485-5p mimics and si-Osx), after the induction of osteogenic differentiation, the cell viability of BMSCs and osteogenic markers were determined. RESULTS: In our work, miR-485-5p was found up-regulated in patients with osteoporosis by comparing with health cases. Besides, during osteogenic differentiation, miR-485-5p was suppressed. These results suggest miR-485-5p has a negative regulating effect. To research potential target of miR-485-5p, we checked it in three publicly available algorithms, TargetScan, miRDB and microRNA. We found that Osterix (Osx) is a direct target of miR-485-5p, and Luciferase assays confirmed our hypothesis, the subsequent experiments showed that decreased expression of Osx resulting from the up-regulation of miR-485-5p could restrain the cell viability and the expression level of osteogenic markers CONCLUSIONS: Our research revealed the promote function of miR-485-5p on osteoporosis, indicating that miR-485-5p could be a potential therapeutic strategy for the treatment of osteoporosis.