Abstract: To deal with the growing electromagnetic hazards, herein a Co@CuFe₂O₄ absorbing agent with excellent impedance matching at thin thickness was obtained via an innovative route of ball-milling assisted chemical precipitation and annealing. The as-prepared composite possesses excellent interface polarization ability due to sufficient contact between CuFe₂O₄ NPs and flat Co, and this compressed Co lamella can also provide sufficient eddy current loss. Moreover, the dipole polarization, electron hopping/conduction, and structural scattering also contribute to the broadband microwave absorption of the composite. Thus, the minimum microwave reflection loss achieves −35.56 dB at 12.93 GHz for 1.8 mm thickness, and the broadest efficient absorption bandwidth can reach 6.74 GHz for a thinner thickness of 1.72 mm. The preparation method reported here can be referenced as a new-type route to manufacture electromagnetic absorbers with outstanding performance.