The absorption and fluorescent properties of Yb³⁺ borate glasses were measured. The integrated absorption cross section and stimulated emission cross section of Yb³⁺ borate glasses were calculated. The effects of B₂O₃ content, glass modifiers (Zno and BaO) and high valency cations (Ti⁴⁺, La³⁺, Ta⁵⁺ and Nb⁵⁺) on the integrated absorption cross section and stimulated emission cross section of ytterbium borate glasses were studied. Two methods were used to evaluate the stimulated emission cross section of ytterbium borate glasses. It is found that the reciprocity method is more appropriate for calculating stimulated emission cross section of ytterbium laser glasses.