Al-8Ca alloy was prepared by iron mold and copper mold casting with granular heat treatment. The microstructure, phase composition and mechanical properties of the alloy were analyzed. The effect of different solidification rate and heat treatment on microstructure and properties of Al-8Ca aluminum alloy was studied. The results show that Al-8Ca alloy solidified at different cooling rates, and a small amount of primary α-Al is dendritic in microstructure and lamellar in eutectic microstructure, which is composed of α-Al and Al4Ca phases. With the increase of cooling rate, dendritic α-Al become smaller, grains are refined, lamellar spacing decrease, and supersaturated solid solution is formed at high cooling rate. After diffused annealing, eutectic microstructure is melted and change to granule shape, and the grain becomes coarse.