The deformation behavior of three kinds of Mg-Li alloys with different test conditions at ambient and elevated temperatures was studied, and the optimized deformation conditions were obtained. The results showed that the addition of lithium increases the plasticity, but little bit decreases in strength of the alloy. However, the strength may be enhanced through the addition of aluminum into the alloy due to the phase precipitation in the alloy matrix. It is also found that elongation depends mainly on both test temperature and strain rate, and the maximum elongation occurs at 350 degrees C and 5 x 10(-4)S(-1) for alpha-alloy, 350 degrees C and 5x 10(-4)S(-1) for beta-alloy, and 400 degrees C, 5x 10(-4)S(-1) for alpha+beta alloy. Further study revealed that the dual-phase alpha+beta alloy exhibited superplastic deformation behavior at a certain condition under which the structures were refined and the texture was disappeared.