The　natural　porosity　architectures,　polar　functional　groups,　low　density,　and　biocompatibility　of　biomass　carbon　materials　make　them　highly　promising　for　the　development　of　lightweight　electromagnetic　microwave　absorbers.　Sugarcane　bagasse　served　as　the　raw　material　for　this　investigation,　and　sugarcane　bagasse-derived　carbon/FexOy　was　prepared　using　the　in-situ　growth　method　and　temperature　field-directed　casting.　By　adjusting　the　content　of　ferrite　hollow　spheres,　magnetic　conduction　losses　and　heterogeneous　interfacial　polarization　losses　are　improved.　Controlling　the　electrical　conductivity　losses　and　multiple　scattering　structures　of　biomass-derived　carbon　at　different　annealing　temperatures,　impedance　matching　is　achieved　through　the　synergistic　operation　of　various　loss　mechanisms.　BDC@C-1.2-750　exhibited　a　minimum　reflection　loss　(RLmin)　of-46.6　dB　at　a　filler　content　of　only　5　wt%　and　a　thickness　of　1.9　mm　and　obtained　a　maximum　effective　absorption　bandwidth　(EABmax)　of　5.52　GHz　at　the　same　thickness.　The　ice　template　directional　casting　formed　an　orderly　thermal　conduction　path,　providing　channels　for　phonon　and　electron　transport,　which　is　beneficial　for　the　efficient　heat　dissipation　of　the　microwave　absorber.　This　finding　thus　offers　a　promising　technique　for　creating　ultra-lightweight　microwave　absorbers　that　facilitate　heat　dissipation.