The basic research on the correlation between composition， microstructure and properties of Al-Li alloy is reviewed， including the alloying effect and mechanism of main alloying elements Cu and Li， and micro-alloying elements of Mg， Ag， Zn and rare earth （RE）. In the research of main alloying elements， it is described emphatically that the strength is enhanced with Cu+Li total atomic fraction and Cu/（Cu+Li） atomic faction ratio， but the IGC resistance is deteriorated with Cu/Li ratio， the corresponding mechanism is explained. In the research of micro-alloying elements， it is expounded that the samll addition of Mg+X （X=Ag/Zn） increases T₁（Al₂CuLi） precipitation rates and improves the strength， and the effect displays as Mg+Ag+Zn>Mg+Ag>Mg+Zn>Mg. Meanwhile， it is described that Zn addition increases IGC resistance but Ag addition decreases IGC resistance. Furthermore， the adverse and beneficial effects and related mechanism of RE elements in Al-Li alloy with higher Cu/Li ratio and low Cu/Li ratio are summarized， respectively. In addition， the application technology development of spinning， friction stir welding （FSW）， argon arc welding， chemical milling of Al-Li alloy is briefely described.