Abstract With the rapid development of science technology and economic growth, people are attaching more and more attention to health problems. In response to the growing clamor for improvements in medical technology, researches have made tremendous efforts. Many breakthroughs have been brought about by the combination of nanotechnology and biomedicine. One significant discovery has been magnetic hybrid nanomaterials (MHNs), which show excellent potential for application in the integration of diagnosis and treatment of cancer and which overcome the limitations of traditional technologies. This chapter aims to introduce some synthesis methods and spatial structures of MHNs and emphatically depict its possibilities in magnetic resonance imaging-based multimodal imaging diagnosis and hyperthermia-based therapy.