The effects of the additions of Sc and Zr in Al-3Cu-2Li alloy on the microstructure and mechanical properties were investigated.The results show that, composite addition of Sc and Zr in Al-3Cu-2Li alloy causes the formation of primary Al3(Sc, Zr) particle which plays an important role in grain refinement. It also serves as a main strengthening phase, like the phases of δ' and T1 in the alloy. The co-planar slip is reduced because of it and the strength of alloy was improved obviously. The alloy of Al-3Cu-2Li-0.2Sc-0.2Zr possesses the fine grains with an average grain size of 24.2μm. The hardness of the alloy is 119.2HV, and tensile strength is 257MPa. Compared with the alloy without Sc and Zr, the hardness and tensile strength of Al-3Cu-2Li-0.2Sc-0.2Zr increase by 18.8% and 52.9%, respectively. After T6 (480℃/45min water quenching+165℃/20h) processing, the hardness is 174.1HV and tensile strength is 488MPa.