Ovariectomized (OVX) rat models were applied to conduct the effects of combination of soy isoflavones (SIF) and calcium (Ca) on bone mineral density (BMD) and bone calcium content in this study. The OVX rats were allocated to five groups:OVX control group, sham group and 3 treatment groups. Rats in 3 treatment groups were treated by gavage using 6^7 mg/kg BW of SIF plus 16^7 mg/kg BW of Ca, 13^3 mg/kg BW of SIF plus 33^3 mg/kg BW of Ca and 40^0 mg/kg BW of SIF plus 100^0 mg/kg BW of Ca, respectively. Femoral BMD, bone mineral content (BMC) and calcium content were measured after 12-week administration. The results showed that rats in sham group and treated with 40^0 mg/kg BW of SIF plus 100^0 mg/kg BW of Ca had significantly higher BMC, BMD in metaphisis and femoral calcium content than those in OVX control group (P<0.05). It demonstrated that the combination of SIF and Ca could increase BMD and bone calcium content in OVX rats, and inhibite the bone loss induced by estrogen deficiency effect on estrogen deficiency-induced bone loss.