The effect of heat treatment on the microstructure and superconducting properties of the alloy Al-8.3 at% Si-8.5 at% Ge prepared by the splat quenching technique has been studied. The results of structure analyses indicate that the rapidly cooled alloy consists of two phases: a supersaturated α-Al (Si, Ge) solid solution (matrix) and amorphous Al-Si-Ge spheres, these spheres connect with each other and form a continuous canal. After annealing at 100℃ for 50 h., the spheres decrease in size and the continuous canal disappear and some dispersive Si (Ge) granules separate out from the amorphous phase. Two superconducting-normal transitions have been found in the resistance-temperature and resistance-magnetic feild curves of the sample after annealing at 100℃ for 50 h. These results can be interpreted by the existence of two superconducting phases in this sample.