Abstract: OBJECTIVE To investigate the icraiin regulating expression imbalance of glucocorticoid-induced osteogenesis genes by inhibiting GILZ expression in MC3T3-E1. METHODS Mature induced differentiation of MC3T3-E1 were divided into 3 groups, respectively dexamethasone(DEX) group, icraiin(ICR) group and ICR+DEX group. The mRNA expression lever of GILZ, osteoprotegerin(OPG), osteoclast differentiation factor(RANKL), osteocalcin (OC) and alkaline phosphatase (ALP) from different groups were detected by Real-Time RT-PCR. RESULT On the one hand, increase of GILZ by DEX improved the expression lever of RANKL, ALP and the ratio of RANKL/OPG in a dose-dependent manner in MC3T3-E1, but inhibited OPG and OC. On the other hand, inhibition of GILZ by ICR increased expression lever of OPG and OC, but inhibited RANKL, ALP and the ratio of RANKL/OPG also in a dose-dependent manner. Further more, enhancing of GILZ, RANKL, ALP and the ratio of RANKL/OPG induced by DEX could be inhibited in the presence of ICR, but the expression lever of OPG and OC were increased. CONCLUSION Inhibition of GILZ by ICR reduced the ratio of RANKL/OPG, suggesting a physiological role in inhibiting osteoclast maturation. Inhibition of ALP and increase of OC by ICR may improve proliferation of osteoblasts.