Oxidative stress-induced osteoblast dysfunction is the key pathogenic factor of osteoporosis.In order to explore the protective effect of curcumin on the function of osteoblasts under oxidative stress and its mechanism,rat osteoblasts cultured in vitrowere pretreated with 1.25,2.5,5 and 10 μmol/L curcumin,and then treated with 50 μmol/L hydrogen peroxide to eatablish an oxidative injury model.The results of cell proliferation showed that hydrogen peroxide treatment significantly inhibited the proliferation of osteoblasts,and curcumin at various concentrations could significantly enhance the activity of osteoblasts and promote cell proliferation (P  < 0.05).The measurement of oxidative stress indicators showed that hydrogen peroxide treatment significantly down-regulated the activities of total antioxidant capacity,superoxide dismutase,and catalase of osteoblasts,and increased the content of malondialdehyde.Pretreatment with curcumin at various concentrations significantly improved excessive oxidation (P  < 0.05).Furthermore,detection of alkaline phosphatase activity and osteogenic differentiation ability showed that pretreatment with 1.25,2.5 and 5 μmol/L curcumin can significantly up-regulated the alkaline phosphatase activity of osteoblasts under oxidative stress (P  < 0.05),and promoted the formation of mineralized calcium nodules,while 10 μmol/L curcumin did not show a significant effect (P  > 0.05).Overall,2.5 μmol/L curcumin exhibited the best protective effect.Western blotting results showed that curcumin's antioxidant protective effect on osteoblasts may be associated with the inhibition of p38 MAPK activation and the promotion of Wnt signaling pathway expression.These findings indicate that curcumin protects osteoblasts from oxidative stress injury and promotes their proliferation and differentiation by scavenging reactive oxygen species and enhancing the activity of the endogenous antioxidant system in vitro.