Wave-absorbing materials are the key materials for stealth techniques. Because the nanometer materials have the special quantum-sized effect and tunneling effect which can result in excellent electromagnetic wave-absorbing performance, more and more attention has been paid to them in the world. In this paper, the operation principle of the wave-absorbing material is explained, the physical essence of the nanometer wave-absorbing material is presented and the current status of the research on the nanometer coating wave-absorbing material and nanometer structural wave-absorbing material is described. Finally, the development trend of the nanometer wave-absorbing material is given.