Abstract: Tetravalent terbium is not stable in aqueous solution because of the high potential of Tb(IV)/Tb(III)couple, The authors of this paper have obtained the Tb(IV)in aqueous solution of orthotellurate anion. The UVand visible absorption speactra of this solution have showed the existence of Tb(IV) complex, and its absorption band with the highest absorption at 360nm has been observed. The effects of various factors upon the formation and the stabilzation of Tb(IV) have been studied. Ablack-red solid containing Tb(IV) has been seperated from the solution, whose constitution is to be investigated.