As a functional composite material, nickel-coated aluminum powder has been widely used in conductive fillers, electromagnetic shielding materials and other fields due to its advantages of low density, high conductivity and low cost. In this paper, nickel-plated aluminum powder was prepared by a sodium hypophosphite system. The effects of different nickel coating amounts (the percentage of nickel-plating quality to nickel-plated aluminum powder quality) on the morphology, phase, compaction resistivity and electromagnetic parameters of nickel-plated aluminum powder coating were studied. The X-Ray Diffraction (XRD) results proved the successful preparation of nickel-coated aluminum powders with different nickel coating amounts. The Scanning Electron Microscope (SEM) images clearly show the coating effect under different nickel coating amounts. By plating nickel on the surface of aluminum powder, the surface characteristics of aluminum powder are changed, so as to adjust its conductivity, resistance, stability and other properties, thus affecting its electromagnetic performance and wave absorption performance. The results show that the comprehensive absorbing performance is excellent when the nickel coating amount is 40%. The reflection loss of the sample with a thickness of 2.0$$mm is less than $?10$$$dB in the frequency range of 10.17–12.38$$GHz. When the frequency is 10.72$$GHz, the minimum reflection loss reaches $?33.17$$$dB.