Abstract: Multiple myeloma (MM) is a malignant B-cell neoplasm, primarily involving the bone marrow, and some may have extramedullary involvement. Imaging examination is an indispensable tool for comprehensive assessment of MM X-ray and CT have lower lesion detection rate, poor quantitative ability. PET/CT and MRI have great value in the assessment of MM, especially the application of ¹⁸F-FDG and other novel molecular probes, whole-body diffusion weighted imaging (DWI), dynamic contrast-enhanced (DCE) MRI and water-fat separation. The author will review the application and progress of PET/CT and MRI in MM.