A novel hybrid material with excellent microwave absorption property has been designed by decorating reduced graphene oxide with Ba Tb0.2Eu0.2Fe11.6O19/PANI composite, and the effect of graphene content on microwave absorption property has been investigated. The microstructure of the composite is characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, field emission scanning electron microscope, transmission electron microscope and Raman spectroscopy. The mechanism of microwave absorption is discussed minutely. The result shows that the ternary nanocomposites demonstrate unexceptionable microwave absorption property due to its special nanostructures and synergistic effect among BaTb0.2Eu0.2Fe11.6O19, PANI and RGO. The minimum reflection loss can reach -60.9dB at 16.4GHz with a thickness of only 1.95mm, and the corresponding effective absorption bandwidth (below -10dB) is 4.2GHz. BaTb0.2Eu0.2Fe11.6O19/PANI/RGO composite can be one of the most promising microwave absorption materials.