In this study, we tried to offer the possibility of White Hibiscus syriacus L. (WHS) flower extracts as a preven-tive and improving agent of osteoporosis that bone mass reduction is induced by an decrease of osteoblast involved in boneformation and increase of bone resorption by osteoclast activity. As a results, it was found to have antioxidant activity andcontain a flavonoid contents (47.74㎎/g) of the WHS flower. There was cytotoxicity at more than 250㎍/㎖ concentration ofWHS flower extract of RANKL-induced osteoclast in RAW264.7. There were no significant inhibited TRAP activity in theWHS leaf and stem. However, it was confirmed that it is significantly inhibited the differentiation activity of osteoclasts in 50and 100㎍/㎖ concentration of cells of stability levels of only WHS flower extracts (p<0.01). The WHS flower prominentlyinhibited RANKL-induced osteoclast differentiation activity by decreased calcitonin receptor and TRAP mRNA (p<0.01).These results indicate that of osteoclasts differentiation activity is inhibited by protection of oxidative stress due to the anti-oxidant activity of the WHS flower. Therefore, suggesting the WHS flower may be a presents the possibility as a preventiveand therapeutic agents for osteoporosis.