Abstract: In this paper,the relations among the solidified structure,tensile strength and growth rate of castings of Al-33.7% Cu eutectic and Al-25.5%Cu hypereutectic alloys have been investigated by the self-made continuous directional solidification(CDS) equipment.It is shown that the long in situ composite castings with shinig surface, homogeneous composition and structure of Al-Cu eutectic and hyper-eutectic alloys can be produced within a wide range of freezing rate by the CDS technology.