Abstract: Objective : To evaluate the MRI sign of early corticosteroids-induced avascular necrosis of femoral head and the relationship between avascular necrosis of femoral head and total dosage,maximal daily dosage,course of using corticosteroids. Materials and methods : 108 cases with heavy corticosteroids in a short period were enrolled,all examined with plain film and MRI.Analyze obtained image characteristics and the relationship between corticosteroids and avascular necrosis with statistical method. Results : Among the 108 cases,35cases show MRI abnormalities and all negative with plain films.There are statistical significance between avascular necrosis of femoral head and total dosage,maximal daily dosage,course of using corticosteroids. Conclusion : MRI can diagnose early avascular necrosis of femoral head,the single and double line sign have specificity.Corticosteroids can induce avascular necrosis of femoral head.