In this paper, an investigation of the relationship among the composi tions, properties and microstructures in Al-Cu cast alloys was described. It. was found that the transition metals such as manganese and zirconium provided an outstanding function to both the improvement on thermal stability and the increase in heterogeneity of the matrix structures. The rare-earth elements should be considered as the strengthening effect on the grain boundries by forming netty or skeletonal stable intermetallic compounds.