Abstract: Development of lightweight and flexible thin films for electromagnetic interference (EMI) shielding is of great significance. In this paper, RGO@SiC porous thin films were prepared for EMI shielding. The porous structure was easily obtained by 3 s of solid phase microwave irradiation, which resulted in an efficient reduction of GO and a significant increase of the film thickness from around 20 to 200 μm. The SE_T of the RGO@SiC porous thin film reached 35.6 dB, while the SE_R was only 2.8 dB. The addition of SiC whiskers was critical for the multi-reflection, interfacial polarization and dielectric attenuation of EM waves. Further, the multilayer composites with a gradient change from transmission to reflection were constructed by stacking the RGO@SiC porous films and using multi-walled carbon nanotubes buckypaper as the reflection layer. The highest SE_T reached 75.1 dB with a SE_R value of 2.7 dB and a thickness of about 1.5 mm. We believe the porous RGO@SiC thin films were promising for designing multilayer or sandwich structure as EMI absorption packaging or lining materials.