Abstract: OBJECTIVE To prepare tenofoviralafenamide D-(-)-tartaric acid salt (2:1) and to study its stability.METHODS Tenofovir (PMPA) was utiliazed as the starting material,condensed with triphenylphosphite,chlorinated by thionyl chloride,and then condensed with L-alanine isopropyl to obtain tenofoviralafenamide.Tenofoviralafenamide was reacted with D-(-)-tartaric acid to form the salt.RESULTS The chemical structure of tenofoviralafenamide D-(-)-tartaric acid salt (2:1) was confirmed by 1H-NMR,31P-NMR,MS.The stability of the compound was also studied and compared with tenofoviralafenamide hemifumarate.CONCLUSION The results showed that D-(-)-tartaric acid salt has a better effect on stability than hemifumarate salt.It is worthy to be futher developed.