The influence of Al content on the microstructure of FeNiCrAl/NiAl composite prepared by thermite reaction was studied. The results show that the NiAl intermetallic compound and the FeNiCrAl present different microstructures morphologies with increasing of Al content. When the Al content is low, NiAl phase exists as particulate inside the grains, and as lath structure in the grain boundary. With the increase of Al content, the intertexture structure first appearing near the grain boundary extends into the grains. Finally a consistent intertexture structure is formed. However, with the further increase of Al content, the size of intertexture structure decreases and even disappears inside the grains. The reason of these microstructure morphology changes was discussed.