With the increasing development of electronic equipment and telecommunication systems, electromagnetic interference and interference have become one of the important challenges of modern technologies. Therefore, the development of lightweight, thin, and high-efficiency microwave absorbers is essential to increase the reflection and increase the dissipation of electromagnetic energy. In this study, MoSe2/MMT nanoparticles synthesized by hydrothermal method were loaded on activated carbon at ratios of 1:1 and 1:3 to create a hybrid composite structure with uniform dispersion of active carbon. The porous structure of activated carbon has enhanced charge transfer and interfacial polarization by providing high specific surface area, multiple transfer paths, and interfacial boundaries. The microwave absorption properties study shows that the MoSe₂/MMT-AC(1:3) nanocomposite sample with the lowest reflection loss of -72.30 dB and a bandwidth of about 4 GHz in the range of 8–12 GHz, gave more than 90% electromagnetic absorption and superior performance.