Few-layered Ti₃C₂T_x MXene was prepared by ionic intercalation and sonication-assisted method. Porous three-dimensional (3D) Ti₃C₂T_x MXene/C hybrid foam (MCF) was fabricated by sol-gel followed by thermal reduction. The MCF/epoxy EMI shielding nanocomposites were obtained via vacuum-assisted impregnation followed by curing process. When the mass fraction of MCF was 4.25 wt% (MCF-5), the MCF-5/epoxy EMI shielding nanocomposites exhibited the optimal electrical conductivity of 184 S/m and the maximum EMI SE of 46 dB, 3.1 × 104 and 4.8 times higher than that of MCF-0/epoxy nanocomposites (without Ti₃C₂T_x MXene), respectively. Furthermore, the corresponding Young''''s modulus of 3.96 GPa and hardness of 0.31 GPa was increased by 13% and 11%, respectively. Conductive networks can realize the attenuation and dissipation of electromagnetic waves by multiple reflection & reabsorption, and absorption is main shielding mechanism. Unique 3D conductive networks of MCF would expand wider application of the Ti₃C₂T_x MXene/polymer-based nanocomposites in high-tech EMI shielding fields.