Y 3 Fe 5 O 12 /BaFe 12 O 19 (YIG/BaM) composites were synthesized via the conventional solid-state reaction method. The phase composition and surface morphology of the composites were investigated using XRD and SEM, respectively. The YIG phase and BaM phase can coexist without any secondary phase for all the composites and the composites are very dense. The dielectric and magnetic properties of the composites were studied. The results show that the YIG/BaM composites have giant dielectric constants and very high magnetizations simultaneously. The dielectric behavior of the YIG/BaM composites can be explained by Maxwell–Wagner Model. Additionally, the coercivity of the composites slightly increases with increasing YIG concentration, which indicates that the composites are also candidate materials for permanent magnet.