High-density MoSi(2)/Al(2)O(3) ceramic composites were prepared by hot-press sintering using MoSi(2) powders and alpha-Al(2)O(3) powders as starting materials. The mechanical and dielectric properties of these composites were studied. The results showed that both the real part and the imaginary part of the complex permittivity increased with the increasing MoSi2 content over the frequency range of 8.2-12.4 GHz, which means that the dielectric performance of the composites can be adjusted mainly by controlling the MoSi(2) content. On the other hand, high strength and high hardness were also obtained in these composites with MoSi(2) as the reinforcing phase. These results indicated that the MoSi(2)/Al(2)O(3) composite was a promising material with both the electromagnetic wave absorbing and the load-bearing abilities.