Abstract: In this paper, the solidifying structure of alumina short fiber reinforced aluminum-silicon alloy composite is studied on the basis of domestic alumina short fibers. The results of the study indicate th at the aluinina short fibers can serve as propitious sites for heterogenous nucleation of the silicon phase in aluminum-silicon alloys, and are favorable to form refined grains of the matrix alloy and reducing microsegregatin of the alloy during the solidification of the compositese.