Objective To explore the difference between bone marrow edema syndrome (BMES) and avascular necrosis of femoral head (ANFH). Methods Recent original articles about BMES and ANFH were extensively reviewed, and were comprehensively analysed. Results The pathology, pathogenesis, clinical features, treatment selection, and prognosis are different between these two diseases. Conclusion BMES and ANFH are two different diseases. Micro-fracture may be the cause of bone marrow edema.