Abstract: To address the potential hazards of electromagnetic radiation and interference on electronic equipment operation and potential harm, M-type hexagonal strontium ferrite (SrFe₁₂O₁₉) nanosheets were prepared by the hydrothermal method, and a series of SrFe₁₂O₁₉/Ag₃PO₄ nanocomposites were synthesized by depositing different amounts of silver phosphate (Ag₃PO₄) nanoparticles onto the strontium ferrite surfaces through an ion-exchange process. The crystal structure and micromorphology of the materials were characterized by X ray diffraction (XRD) and scanning electron microscope (SEM), while the magnetic properties and electromagnetic wave absorption performance were evaluated using a vibrating sample magnetometer (VSM) and vector network analyzer (VNA), respectively, to investigate the effect of different amounts of silver phosphate attachment on the microwave absorption properties of the nanocomposites.The results indicate that Ag₃PO₄ nanoparticles are uniformly distributed on the hexagonal strontium ferrite sheets, with their loading density significantly increasing at higher Ag₃PO₄ concentrations. When the Ag₃PO₄ mass fraction is 3% with an absorbing coating thickness of 5.0 mm, the minimum reflection loss reaches −23.6 dB at 7.3 GHz. Increasing the coating thickness to 5.5 mm yields an effective absorption bandwidth (reflection loss < −5.0 dB) of 4.0 GHz (3.9–7.9 GHz), confirming that the SrFe₁₂O₁₉/Ag₃PO₄ nanocomposites exhibit outstanding microwave absorption performance and promising application prospects in this field.