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 in multiple myeloma (MM). The authors systematically examines the application of PET/MRI in MM, focusing on imaging agents, acquisition protocols, and its role in disease diagnosis, detection of minimal residual disease, and prognostic stratification, which aims to further elucidate the clinical utility of PET/MRI in precision medicine for MM, thereby facilitating the development of personalized therapeutic strategies and optimizing treatment monitoring systems.