Abstract: The Fe-filled single-walled carbon nanotubes (SWCNTs) were fabricated by a DC arc discharge method. After purification process and then doped the very substance into the nanocrystalline M-type barium hexaferrite (BaFe₁₂O₁₉), which was synthesized by a sol-gel auto-combustion method. The electromagnetic parameters of the samples were tested using coaxial method, and microwave absorption properties of SWCNTs/BaFe₁₂O₁₉ composite with different doping ratios were investigated. The results indicate that the magnetic loss of composite SWCNTs/BaFe₁₂O₁₉ is mainly attributed to the natural resonance and exchange resonance. When doping 2% mass fraction of SWCNTs, the maximum reflection loss of composite can reach 24.85 dB and the frequency band width of above 10 dB is 6.30 GHz, which is a wide microwave absorption frequency band.