Abstract: OBJECTIVE To investigate the effect of different doses of total flavones of Drynariae Rhizoma on the expression of estrogen and orthopantomography(OPG), receptor activator of NF-κB(RANKL), receptor activator of NF-κB ligand(RANK) in osteoporotic rats through administration by gavage, and explore the effect of total flavones of Drynariae Rhizoma on the bone metabolism in osteoporotic rats model. METHODS osteoporotic rats model were established by cutting out their ovaries, were given estradiol (0.1 mg·kg^-1) and low, middle, high dose (0.054, 0.108, 0.216 g·kg^-1·d^-1) of total flavones of Drynariae Rhizoma by gavage for 3 months. Then draw their arterial blood. the changes of estrogen level were observed by radioimmunoassay and OPG, RANKL, RANK level by ELISA. RESULTS Campared with model control 2 group, the estrogen and OPG content were obviously increased (P<0.05), the RANKL and RANK content were significantly decreased (P<0.05). At the same time, the estrogen and OPG rose along with the dose of total flavones of Drynariae Rhizoma while the RANKL and RANK dropped. CONCLUSION different doses of total flavones of Drynariae Rhizoma can all affect OPG/RANKL/RANK axial system, and the effect rise along with the concentration of total flavones of Drynariae Rhizoma, which may be realized by increasing the OPG level and decreasing the RANKL and RANK level.