Objective To study the endogenous glucocorticoid on rat femoral head microenvironment of 11 hydroxysteroid dehydrogenase expression ,and to discuss the influence of combined with femoral head pathological changes of the corresponding mechanism .Methods Sixty SD rats were divided into control group ,1‐month group ,3‐months group ,each 20 rats in group .1‐month group and 3‐months group inject cortisone acetate in the abdominal cavity intraperitoneal for 1‐month or 3‐months each .Im‐munohistochemical ,immunofluorescence ,Real‐time qPCR ,HE staining were employed in this study .Results From immunohisto‐chemical ,immunofluorescence ,Real‐time qPCR ,the 11 hydroxysteroid dehydrogenase content of 1‐month group and 3‐months group were higher than that of the control group(P<0 .05) .From HE staining we detected 1‐month group in the bone marrow cavity in‐creased in fat cells ,3‐months group subchondral trabecular bone density decreased ,compared with the control group(P< 0 .05) . Conclusion Supplement of corticosterone could promote rat femoral head microenvironment 11 hydroxysteroid dehydrogenase ex‐pression and subchondral trabecular bone density decrease .