Highly Ho3+/Tm3+ co-doped Bi2O3-B2O3-Al2O3-BaF2 glasses were fabricated using the melt-quenching technique. The emission, radiation, and gain characteristics of the glass samples at the wavelength of 2.0 μm were examined analyzed. An intense and broad 2.0 µm emission, resulting from the 3F4→3H6 transition of Tm3+ and the 5I6→5I7 transition of Tm3+, was detected under the stimulation of 808 nm LD. The gain coefficient of Ho3+ in Ho3+/Tm3+ co-doped glass reaches 7.81 cm−1(at 2050 nm), which is 7.5 times as high as that of tellurite glass. Meanwhile, the large σemi × Δλeff(39.84 × 10-26 cm3) and σemi × τrad(16.10 × 10-21 cm2 ms) indicated BBTH4 glass possessed a large gain property and broadband. The energy transfer process of Tm3+: 3F4 ↔ Ho3+:5I7 was analyzed, the CD-A is 90 times larger than the CA-D. The Ho3+/Tm3+ co-doped Bi2O3-B2O3-Al2O3-BaF2 glasses show potential as broadband mid-infrared emission gain material.