Objective To study the regulatory effect of salidroside(SAL)on mouse osteoblasts under hypoxic conditions simulated by cobalt chloride(CoCl2).Methods CoCl2 was used to simulate hypoxic conditions(1%02)to establish an in vitro hypoxic model.MTS method was used to study the effect of different concentrations of SAL on the proliferation of MC3T3-E1 cells under hypoxic conditions.The effect of SAL on the differentiation of MC3T3-E1 cells under hypoxic conditions was studied by disodium phenyl phosphate method.Real-time fluorescence quantitative PCR(RT-qPCR),Western blot and ELISA were used to detect the mRNA and protein expression levels of hypoxia-inducible factor-1α(HIF-1α)and downs.Results 0.5 mmol/L CoCl2 was used to simulate the hypoxic(1%02)environment.Hypoxia could significantly inhibit the proliferation and differentiation of MC3T3-E1 cells.After pretreatment with SAL,the proliferation and differentiation of MC3T3-E1 cells were significantly promoted.SAL(10 nmol/L)significantly up-regulated the mRNA expression levels of HIF-1α and VEGF and the protein expression level of HIF-1α,and down-regulated the expression of VEGF protein.Conclusion SAL promotes the proliferation and differentiation of mouse osteoblasts under hypoxia.The specific mechanism needs to be further studied,which may be related to the HIF-1α/VEGF signaling pathway.