Background <p>Postmenopausal osteoporosis (PMO) is acknowledged as a principal category of osteoporosis (OP). The aim of this study was to investigate the level of miR-370-3p in PMO patients and its predictive effect on osteoporosis in postmenopausal women, and to explore the molecular mechanism of miR-370-3p on PMO.</p> Methods <p>The expression of miR-370-3p was assessed using RT-qPCR. Cell proliferation of MC3T3-E1 cells was evaluated through CCK-8 assays. Cell apoptosis was detected by flow cytometry. The direct interaction between miR-370-3p and INO80 was confirmed via dual-luciferase reporter assays.</p> Results <p>The level of miR-370-3p was found to be upregulated in osteoporosis patients, and miR-370-3p played a significant role in regulating the proliferation, apoptosis and differentiation of osteoblasts. In addition, miR-370-3p targeted INO80 and affected the disease progression of PMO.</p> Conclusions <p>miR-370-3p/INO80 may serve as a promising biomarker for both the diagnosis and therapeutic management of PMO.</p>