▎ 摘　　要

NOVELTY - Preparation method of carbon foam material involves (i) mixing a mixed solution of paraffin wax and ferroferric oxide with an aqueous dispersion of nanocellulose and graphene oxide, and ultrasonically treating to obtain pickering emulsion gel, (ii) freezing the pickering emulsion gel to obtain composite foam, and (iii) annealing the composite foam to obtain the product. USE - Method useful for preparation of carbon foam material for electromagnetic wave absorption application (all claimed). ADVANTAGE - The method adjusts or switches the strength of the electromagnetic wave absorption performance of the composite foam through different compression strains, meets the requirement of practical application, improves the impedance matching of the carbon foam material and is guaranteed that electromagnetic waves can enter into the carbon foam material.