The development of high-performance electromagnetic interference (EMI) shielding materials is urgently needed to mitigate electromagnetic radiation pollution. Two-dimensional transition metal carbides (MXenes) are promising EMI shielding materials because of their high metallic electrical conductivity. However, tuning the EMI shielding performance of MXene composites remains challenging via the structure engineering strategy. Herein, we develop a layer-by-layer assembling strategy to construct multilayer sandwiched hollow magnetic Fe3O4 nanospheres (HFO)/MXene on flexible nonwoven fabrics. The fabricated Fe3O4/MXene composite fabrics (HFMs) exhibit low sheet resistance (4.6 Ω/□), super-hydrophobicity, self-cleaning, and good EMI shielding performance (EMI shielding effectiveness of 33.28 dB). More importantly, the EMI shielding mechanism of HFMs is tunable according to the loaded active materials. Thus, the mechanism can alternate from absorption to reflection. Moreover, the HFMs exhibit good electrothermal performance and can be used as a wearable heater for personal thermal management. This work provides a new approach for the structural design of high EMI shielding materials, and paves the way for the development of wearable electronics.