The IMC/Al alloy matrix composites were prepared by reaction synthesis between Fe and Al using Fe powder or Fe-Al mixed powder. For the composites fabricated with AC4C melts and Fe powder, when the particle size of Fe powder was －100＋140mesh and －230＋270mesh, and the mold and melt temperature were 400℃ and 680℃, respectively, but in the case of lower particle size(－325mesh) of Fe, the mold temperature of 450℃ and the melt temperature of 610℃ were observed. For the composites prepared with mixed powder of －325mesh Fe and Al powders, the optimum process condition was the mold temperature of 650℃ and the melt temperature of 610℃. The amount of reaction products at the interface between matrix and particles increased with decreasing particle size of Fe powder for the composites fabricated with Fe powders, while it decreased with decreasing the amount of Fe for the composites made with －325mesh Fe-Al mixed powder. The fine Al-Fe binary intermetallic compound(＜－10㎛) was observed for the composite fabricated with mixed powder of Al-10wt%Fe.