In this paper, two morphological high-entropy alloy particles (Al0.25Cu0.75FeCoNi) were prepared by mechanical alloying. One is ellipsoidal particles (average particle size 53μm, no control agent), the other is flake particles (average particle size 15μm, with control agent). High-entropy alloy particles reinforced cast aluminum alloy (volume 5 vol.%) were prepared by squeeze casting. The influence of different reinforcement morphology on the microstructure and mechanical properties in composite was analyzed. The results show that in preparation for precast block, ellipsoidal ones are easily mixed uniformly with aluminum powder, while the flake are prone to agglomeration. The tensile strength of the ellipsoidal and the flake particles reinforced composites reached 162 MPa and 174 MPa, respectively, which was 12.5% and 20.8% higher than that of matrix alloy, but the elongation was significantly lower. Fracture analysis showed that the fracture of ellipsoidal particles reinforced composite was dominated by the tear of the matrix, while the flake particles reinforced composite was dominated by the rupture of agglomeration.