Stauntonia hexaphylla (SH), a medicinal plant in the Lardizabalaceae family, holds traditional significance in East Asian countries for its therapeutic properties, particularly in treating rheumatism. Steam processing is a common method employed to augment the therapeutic properties of SH, prompting the need for a detailed investigation into the chemical and biological changes induced by this process. Comparative analyses revealed significantly higher 5-Hydroxymethylfurfural (5-HMF) content, total flavonoid and phenolic content, and antioxidant activity in steamed SH fruit (SHF) samples compared to unprocessed ones. Furthermore, the study explored the effects of steamed SHF extracts on bone health using an in vitro model simulating osteoclast in Raw 264.7 cells and osteoblasts in MC3T3E1 cells. Notably, steamed extracts demonstrated a dual effect on bone health by promoting alkaline phosphatase activity, calcium nodule, and collagen formation in osteoblasts, while inhibiting tartrate-resistant acid phosphatase (TRAP) activity in osteoclasts. Steamed SHF extracts were able to restore the aberrant gene expression of osteoclastogenesis indicators including TRAP, NFTAc1, RANK, MMP9, c-Fos and TRAF6. Additionally, the expression of the osteoblastogenesis biomarkers ALP, Runx2, BGLAP, Col1a1, and OPG were boosted by steaming to levels greater than those in the untreated control group, suggesting that steaming can be used to improve the properties of proteins. The component 5-HMF actively promotes ALP and inhibits TRAP activities. Hence, these results are expected to aid in confirming the efficacy of herbal medicines and identifying suitable materials for medicinal applications.