The present work was aimed to examine the variation of precipitations and mechanical properties by thermomechanical treatments(TMT) in Al-2.19wt%Li and Al-2.0wt%Li-0.11wt%Zr alloys. This study was perfomed by TEM, SEM observation, DSC, electrical resistance measurement, hardness and tensile strength measurment. First peak of resistivity aged at 90℃ was caused by precipitation of δ` -precursor phase, and second peak was caused by precipitation of δ` phase. According to this result, the precipitation process of Al-2.19wt%Li alloy was as follow : SSSS→δ` -precursor phase→δ`(Coherent→Semi-coherent)→δ In a Al-2.0wt%Li-0.11wt%Zr ternary alloy, the first peak of resistivity was appeared at initial aging heat-treatment. It is result from exsistant of δ` -precursor phase. The effect acceleration in a binary alloy was not appeared and the over-aging ternary alloy was accelerated with increase of the reduction rate. 1t is caused by combination effect of δ` and composite phase.