Cast Al-Li alloys can be used to shape complex thin-walled components and currently have broad application prospects in aerospace, military and other fields. Refining the microstructure and improving the strength and plasticity of cast Al-Li alloys is highly important for practical applications. In this work, Al-2Li-2Cu-0.5Mg-xSc alloys containing different Sc contents were prepared by metal mold casting, and the effects of the Sc content on the microstructure and  mechanical properties of the alloys were analysed. The results indicate that as the Sc content gradually increases, the alloy grains transform from dendrites to near-equiaxed grains, and the grain size gradually decreases. The δ′(Al 3 Li) phase tends to nucleate with the Al 3 Sc phase, forming Al 3 (Li, Sc) composite particles that are not easily cut by dislocations during deformation, reducing the coplanar slip caused by Al 3 Li particles. When 0.3 wt. %Sc is added, the alloy has good comprehensive mechanical properties, and the yield strength, tensile strength and elongation can reach 381.3 MPa, 449.5 MPa and 5.8%, respectively, after the peak aging treatment at 175 ℃/32 h.