Abstract: In this paper,the heat treatment technique,the microstructure and the properties of the national Al-Li alloy were studied.The results show that after being solution heatt reated(527±3℃,30 mimutes,water quenched)and art ificially aged(190℃,19 hours),The properties of Al-Li alloy are,b=516~567 MNm^-2,δ=6.2~6.3%;,and the microstueture appears homogeneous,and which are better than that of ageing at normal at mospheric temper at ure.Increasing the time of solution heat treat ment at preverset emperture,the streng thof Al-Li alloy seems to be better.If the ageing time at normal atmospheric temperature is over 35 days,the mechanical property is lower.