Abstract: PET/MRI is an advanced imaging device that integrates PET and MRI, which can simultaneously image the metabolic and anatomical structures of tissues and organs, and has unique advantages in many diseases, especially its clinical application value in multiple myeloma (MM) deserves attention. The authors systematically examine the application of PET/MRI in MM, focusing on imaging agents, acquisition protocols, and its role in disease diagnosis, detection of minimal residual diseases, and prognostic stratifications, which aims to further elucidate the clinical value of PET/MRI in precision diagnosis and treatment of MM, thereby facilitating the development of personalized therapeutic strategies and optimizing response monitoring frameworks.