Al-4.5Cu-3Ce alloy semi-solid slurry has been prepared by using slope vibration casting. The effects of the pouring temperature, slope length, vibration amplitude and vibration voltage on alloy solidification microstructure were researched. Experiments show that these parameters play a significant role on the alloy microstructure. The uniform, small equiaxed microstructure of Al-4.5Cu-3Ce alloy can be acquired by water-cooled copper mold casting at 680°C with slope length of 20cm, vibration amplitude of 2cm and vibration voltage of 80v. Its average grain diameter is 28.1um with average roundness coefficient of 0.82.