The invention provides a carbon fiber wave-absorbing material and a preparation method thereof. The carbon fiber wave-absorbing material comprises carbon fiber felt and alloy, and the alloy covers thesurface of the carbon fiber. The surface of the carbon fiber is covered by the alloy so that the weight of the carbon fiber wave-absorbing material is low, the surface density is merely 350g-400g persquare meter, the material is soft, and the storage and the usage are convenient.