MicroRNA (miRNA) is a kind of important gene expression regulatory molecules during biological process, but its regulation mechanism in metabolic process of bone tissues has not been completely clarified. In this review, the regulation of miRNA on osteoblast differentiation in microgravity environment was discussed. The positive and negative regulation of miRNA was summarized, respectively, with focus on introducing the mechanism of different genes. Some miRNA molecules that have important effects on bone metabolism under microgravity were enumerated. MiRNA plays an important role in regulating and controlling bone metabolic diseases in microgravity environment, and its related studies are significant for the prevention and treatment of bone loss induced by weightlessness.