Magnetic hyperthermia therapy (MHT) is a noninvasive treatment strategy that uses alternating magnetic fields (AMFs) to excite magnetic nanomaterials for localized heat generation and selective tumor ablation. Compared to traditional hyperthermia techniques (i.e., photothermal or radiofrequency heating), AMFs exhibit unique advantages, including deep-tissue penetration and negligible energy attenuation, demonstrating significant potential for treating visceral tumors such as hepatocellular carcinoma and glioblastoma. As representative magnetothermal materials, iron oxide nanoparticles (IONPs) can overcome the limitations of stand-alone hyperthermia through functionalization strategies such as heteroelement doping (i.e., Mn2+, Co2+), nucleic acid/drug conjugation, polymer hybridization, or other types of magnetic hyperthermia materials. These modifications can enable synergistic magneto-chemotherapy/PTT/PDT, gene therapy, and multimodal imaging-guided applications. This review systematically summarizes MHT nanomaterial classification, constituents, and applications in disease treatment. Additionally, it analyzes the challenges and prospects of MHT nanomaterials in tumor targeting, biosafety, and clinical translation, offering theoretical insights for developing next-generation intelligent MHT agents.