A kind of graphene composite (rGO/Co_0.5Zn_0.5Fe₂O₄) was synthesized with the graphene oxide (GO) prepared from natural flake graphite and cobalt-zinc ferrite (Co_0.5Zn_0.5Fe₂O₄) manufactured by the hydrothermal method. The structure of composites was characterized by X-ray diffraction (XRD), Raman spectrometer (Raman) and the Fourier-transform infrared spectroscopy (FT-IR). Morphology, electromagnetic loss properties, Debye relaxation, and microwave absorbing properties of rGO/Co_0.5Zn_0.5Fe₂O₄ were investigated by transmission electron microscope (TEM) and vector network analyser (VNA). Sharp peak of graphene oxide was changed from 2θ=9.74° to 24.15° in the XRD patterns and the oxygen functional group disappeared after the composite reaction, which demonstrated that GO was successfully reduced to rGO. The graphene was embedded with cobalt-zinc ferrite, observed by transmission electron microscope, with its dispersion worse with the loaded Co_0.5Zn_0.5Fe₂O₄ increasing. Absorbing property of rGO/Co_0.5Zn_0.5Fe₂O₄ composite prepared with w(Co_0.5Zn_0.5Fe₂O₄) : w(GO)= 2 : 1 is the best with the minimum reflectivity of -36.89 dB at 15.11 GHz and the effective absorption frequency bandwidth of 3.74.