The MoS2@[email protected]3O4 composite was skillfully synthesized via a novel one pot method. No any separation step during the synthesis process, and the Fe2+ was successively utilized to prepare the Ppy and Fe3O4, which can achieve a high utilization of raw materials. The characterization about microstructure, crystal form, elemental composition and surface functional groups verify the structure of MoS2@[email protected]3O4. Its hysteresis loop indicates that the composite performs typical soft magnetism behavior, with a magnetic saturation value of 20.3 emu.g−1, which is helpful to improve the magnetic loss for EM wave absorbing. The reflection loss curve suggested that the composite exhibits superior EM wave absorption performance, with a minimum reflection loss value of –32 dB at the specimen thickness of just 2.0 mm due to the fair electromagnetic matching, interface polarization and interface relaxation. In addition, the one pot method used in this work can promisingly be applied to prepare other similar composites such as carbon [email protected]@Fe3O4, [email protected]@Fe3O4.