ObjectiveTo investigate the effect of micro RNA (miR)-335-5p regulating bone morphogenetic protein 2 (BMP-2) on the osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs).MethodshBMSCs were cultured in vitro and randomly divided into control group (group A), miR-335-5p mimics group (group B), miR-335-5p mimics negative control group (group C), miR-335-5p inhibitor group (group D), and miR-335-5p inhibitor negative control group (group E). After grouping treatment and induction of osteogenic differentiation, the osteogenic differentiation of cells in each group was detected by alkaline phosphatase (ALP) and alizarin red staining; the expressions of miR-335-5p and BMP-2, Runt-related transcription factor 2 (Runx2), osteopontin (OPN), and osteocalcin (OCN) mRNAs were detected by real-time fluorescence quantitative PCR analysis; the expressions of Runx2, OPN, OCN, and BMP-2 proteins were detected by Western blot.ResultsCompared with group A, the relative proportion of ALP positive cells and the relative content of mineralized nodules, the relative expressions of BMP-2, miR-335-5p, OPN, OCN, Runx2 mRNAs, the relative expressions of Runx2, OPN, OCN, and BMP-2 proteins in group B were significantly increased (P<0.05); the above indexes in group D were significantly decreased (P<0.05); the above indexes between groups C, E and group A were not significantly different (P>0.05).ConclusionmiR-335-5p can up-regulate BMP-2 expression and promote osteogenic differentiation of hBMSCs.