Abstract: Multiple myeloma (MM) is a malignant disease characterized by abnormal clonal plasma cell proliferation and is the second most common malignant tumor in the blood system. The exact cause of this disease remains unclear. Most patients present with clinical manifestations such as bone destruction, renal insufficiency, and anemia, which seriously affect the prognosis of patients and are still incurable. Previous studies demonstrated a significant increase in the serum fibroblast growth factor-23 (FGF-23) among patients with MM. FGF-23 is not only involved in bone destruction and the formation of blood vessels in the bone marrow microenvironment but also regulates calcium and phosphorus levels in vivo. Moreover, recent studies have revealed a close relationship between FGF-23 regulation and iron metabolism. This connection could potentially play a significant role in MM progression and the development of associated complications. Moreover, it has been linked to a poor prognosis. Further studies on FGF-23 regulation in patients with MM are expected to become a new predictive factor for evaluating the prognosis of clinical target organ damage. This study may provide new insights for targeted therapy.