Objective To summary the functional roles and molecular mechanisms of microRNA (miRNA) in osteoblast differentiation so as to supply information for basic and cl inical researches. Methods Recent l iterature concerning miRNA in osteoblast differentiation was reviewed. The information was classified and summarized. Results miRNAs critically regulate bone morphogenetic protein, transforming growth factor β, and Wnt/β-catenin signal ing pathways during osteoblast differentiation. In pathological conditions, especially in some disorders of abnormal osteoblast differentiation, downregulated miRNA expression has been observed. Conclusion miRNA may represent a novel biomarker for diagnosis, and a candidate target therapies for the disorders with abnormal osteoblast differentiation.