With the growing threat of electromagnetic interference, developing lightweight and flexible multiband protection materials to shield humans from harmful electromagnetic interference is becoming particularly crucial. However, existing protection materials are bulky and designed primarily for single-band electromagnetic waves. This paper constructs bismuth/tungsten oxide/multi-walled carbon nanotube/polyacrylonitrile (Bi/WO3/MWCNTs/PAN) nanofiber composites with multilevel nanostructures through electrospinning and post-processing technology for effective NIR/UV/X-ray Multiband Electromagnetic Protection. The porous structure, combined with the strong absorption capabilities of MWCNTs for low-frequency electromagnetic waves and high photoelectric effects of high atomic number materials (Bi/WO3), synergistically achieves remarkable electromagnetic protection performance. This includes 99.6 % near-infrared shielding and 99.95 % against ultraviolet (thickness: 0.12 mm), along with 55.2 % X-ray attenuation and a mass attenuation coefficient of 13.94 cm2 g−1 at 33 keV (thickness: 1.92 mm). Light weight (0.3 g cm−3), fantastic flexibility, and moisture permeability (9.22 kg m−2 d−1) endow the material with outstanding wearable performance. In addition, Bi/WO3/MWCNTs/PAN also possesses excellent thermal insulation performance (36.96 mW m−1 K−1), temperature resistance (289.8 °C), and good electrical insulation. These exceptional performances demonstrate its enormous potential for application in electromagnetic shielding and provide new ideas for designing advanced multiband electromagnetic protection materials.