Abstract: To study the electromagnetic properties of the ferrite and the influences of the ferrite addition and the thickness of samples on the properties of the materials, foam wave absorbing materials were fabricated by introducing some ferrite and using glass and ceramic granulated material as base materials and carbon black as vesicant, with the processes of ball milling, sintering, foaming and annealing. The electromagnetic properties of ferrite had no significant change after the heat treatment at 900℃. The wave absorbing performance of materials with 5% and 10% ferrite were better than that of the materials with 15% and 20% ferrite contents, which was attributed to the fact that the incorporation of the ferrite influenced the porous structure of foam materials. Moreover, when content of ferrite was 10%, the wave absorption of the material increased with increasing samples’ thickness. The effective absorption bandwidth (reflectivity < -10dB) of 50mm thick material reached 18GHz, and its lowest reflectivity was -23.4dB.