Objective To explore the mechanism of glucocorticoid induced osteoporosis and bone forming of the statins by investigating the effects of simvastatin on the PPAR gamma.Methods By establishing the glucocorticoid induced osteoporosis model of rat and after treatment with the simvastatin for five weeks, the PPAR gamma expression was examined in sections of vertebra samples.Results \ The PPAR gamma expression was, respectively, the lowest in the non steroids control group, the highest in the steroids control group but decreased in a dose dependent manner after being treated by simvastatin in the treatment group.Conclusion\ PPAR gamma may play an important role in glucocorticoid induced osteoporosis. The simvastatin inhibits expression of PPAR gamma and reduces the formation of adipocyte tissue. Osteoblasts and bone formation are increased by regulating bone marrow stromal cell differentiation.