The N,N,N’,N’-tetrabutsuccinylamide(TBSA) was synthesized and purified.The extractability of this diamide for Terbium(Ⅲ) has been studied.The effects of concentrations of nitric acid,extractant,and LiNO3 as well as the temperature influence on the extraction distribution ratios were investgated in detail.The apparent equilibrium constant of extraction has been determined to be(0.77±0.02)L6/mol6at 298K.The enthalpy of the extraction was -25.64kJ·mol-1.The composition of the extracted species was found to be Tb(NO3)3·3TBSA,which was characterized by IR spectromery.