Abstract: Al-20Zn and Al-20Zn-0.5Sc alloys were prepared by melt-casting technique. The microstructure of the as-cast, homogenized, rolled alloys and the tensile properties and damping properties of the rolled alloys were studied and compared. The results show that the grain size of Al-20Zn-0.5Sc alloy was smaller than that of Al-20Zn alloy in the same state. The rolled Al-20Zn-0.5Sc alloy showed higher yield strength, tensile strength, elongation after fracture and high temperature (360 ℃) internal friction than the Al-20Zn alloy. The Al₃Sc nanophase formed by the reaction of scandium and aluminum could pin grain boundaries and dislocations, inhibit recrystallization, and refine grains, so the Al-20Zn-0.5Sc alloy exhibited more excellent tensile properties and high-temperature damping capacity.