The effects of alloying elements on the superplastic properties of Al-Li based alloys had been investigated. The intermediate thermo-mechanical treated(ITMT) Al-2.0wt%Li, Al-2.0wt%Li-1.0wt%Mg, Al-2.0wt%Li-0.12wt%Zr and Al-2.0wt%Li-1.2wt%Cu-1.0wt%Mg-0.12wt%Zr alloys were tested in tension at various temperature (400, 450, 500 and 550℃) and strain rate(6.7×10^(-3), 1.0×10^(-2), 1.6×10^(-2) and 5.0×10^(-2)/sec). The results were as follows : The superplasticity in binary, ternary and pentanary alloys appeared at 500 to 550℃, and good strain rate for superplasticity, 1.6×10^(-2)/sec∼1.0×10^(-2)/sec for a binary alloy and 1.0×10(-2)/sec∼6.7×10^(-3)/sec for ternary and pentanary alloys. A Zr-added ternary alloy had best value of elongation (730%) in four alloys at 550℃ of tension temperature and 1.0×10^(-2)/sec of strain rate. The strain rate was greatly dependent on tension temperature and true strain rate was more than 1.0 at all test temperature and strain rate. In binary and Mg-added teranry alloys, the necks were slightly formed and their fracture surface had lips shape, but Zr-added ternary and pentanary alloy fractured along the grain boundary without necking. Their dislocations moved to grain boundary during superplasticity deformation and arranged perpendicular to grain boundary. Superplastic deformation was made by grain boundary slip of dislocation slip creep and model of core and mantle.