Transparent and uniform tellurite–phosphate glasses were prepared and the reason why the substitution of NaPO 3 for P 2 O 5 can eliminate the coloration of tellurite–phosphate was discussed. The result of TDA indicated that introducing NaPO 3 into tellurite glasses can improve thermal stability of glass hosts. The compositional dependence of absorption cross-sections of 4 I 13/2 , 4 I 11/2 and 2 H 11/2 level, emission cross-section of 4 I 13/2 level, host phonon energy, up-conversion and 1.5μm optical emission intensity as well as and quantum yield for 4 I 13/2 level in PTEr glasses were investigated too. By analyzing obtained data, authors believe that tellurite–phosphate glasses can be used as potential host material for developing optical amplifiers.