The porous hollow BaFe12O19/CoFe2O4 microrods were prepared by an easy and reproducible in situ synthetic method. Cotton cellulose was used as the sacrificial bio-template. The as-prepared hard/soft ferrite composites were homogeneously distributed on the surface of the microrods. It was demonstrated that the porous hollow microrods-like structure and the exchange-coupled interaction between hard and soft ferrites were beneficial to improve the microwave absorption properties. The weight content of the hard/soft ferrite composites was low to 60 wt%, whereas reflection loss could reach to −10 dB in the frequency range of 8.2–16.3 GHz. The fabrication of porous hollow BaFe12O19/CoFe2O4 microrods was an efficient approach to solve the heavy mass problem of the conventional hard/soft ferrite matrix microwave absorption materials. Display omitted •A kind of novel porous hollow BaFe12O19/CoFe2O4 composite microrods was investigated.•The weight content of the hard/soft ferrite composites was less to 60 wt%.•The reflection loss was reach to −10 dB in the frequency range of 8.2–16.3 GHz.