ABSTRACTObjectiveTo investigate the effects of 3’daidzein sulfonate sodium on bone metabolism of ovariectomized rats. MethodsSixty female SD rats were selected and randomly divided into six groups：shamoperation （normal control）, ovariectomized model （model）, ovariectomized with nilestriol （positive control）, highdose, middledose, and lowdose （ovariectomized with 3’daidzein sulfonate sodium 100, 50 and 25 μg•kg－1 ,respectively）. After continuous administration for 6 weeks and 24 h after the last administration, the serum was obtained after anesthesia and contents of the osteocalcin （BGP）, alkaline phosphatase（AKP）, tartrateresistant acid phosphatase （STrACP）, and progesterone were determined. ResultsIn the model control and high dose groups, respectively, the BGP concentration was （5.04±0.05） and （4.82±0.05） ng•mL－1, AKP was （47.31±0.02） ×10－2and （36.90±0.21） ×10－2 U•mL－1, STrACP was （1.72±0.11） and （3.02±0.13） U•L－1, and progesterone was （49.72±2.00） and （53.41±1.12） ng•mL－1. 3’daidzein sulfonate sodium decreased the content of serum osteocalcin and AKP significantly （P＜0.01 ）, but elevated STrACP （P＜0.05） markedly and increased the content of progesterone （P＜0.01）. Conclusion3’ daidzein sulfonate sodium regulates bone metabolism by promoting bone formation.