In the present work Mg-Li-X alloys with different alloying are investigated and the studies are focus on the stability of microstructures and properties of β base Mg-13Li-X alloys. The alloying elements concerned are aluminum, zinc, zirconium, rare earth. The microstructure and corresponding mechanical properties are examined with the aid of DSC analyses, X-ray diffraction and OM observation. The results showed that the hardening effect and the stability of the alloys varied with different addition of aluminum, zinc, zirconium, rare earth elements. The mechanical properties of the alloys greatly depend on the additional elements.