The proportion of the elderly population around the world is constantly increasing, resulting in a higher incidence of osteoporosis among this demographic population. In this study, we aimed to confirm the osteoporosis-inhibiting effect of Astragalus sinicus extract. The cytotoxicity and inhibitive effects against osteoclast differentiation of Astragalus sinicus extract were confirmed through CCK-8 assay and TRAP staining analysis. Moreover, we conducted a comparative analysis of the alterations in mRNA and protein expression of various genes associated with osteoclast differentiation upon treatment with Astragalus sinicus extract, utilizing realtime-PCR and western blotting techniques. As a result, cytotoxicity of Astragalus sinicus extract was not observed, and the inhibitive effect against osteoclast differentiation increased with higher concentrations of Astragalus sinicus extract. Additionally, the transcriptional and translational expression of genes related to osteoclast differentiation were suppressed. Therefore, this result suggested that Astragalus sinicus extract could be both a functional food and a therapeutic agent for treating osteoporosis.