Nd3+/Yb3+co-doped fluorobromide glass samples were prepared by melt quenching. The mid-infrared (MIR) luminescence of the Nd3+/Yb3+co-doped fluorobromide glass was investigated by Br-doping re-duces the phonon state density of the matrix. The 3.9μm MIR luminescence of the samples excited at 793 and 980 nm pump excitation was investigated in detail. There is an effective mutual energy transfer process between Nd3+and Yb3+. It is proved under 793 nm excitation that the luminescence of Nd3+at 3.9 μm is reduced by effective energy transfer from Nd3+:2H11/2 → Yb3+:2F5/2. At the same time, it is proved that the effective energy transfer from Yb3+:2F5/2→Nd3+:2H11/2 under the excitation of 980 nm enhances the luminescence of Nd3+ at 3.9μm. In addition, it is found that the samples still have good infrared (IR) luminescent properties when the temperature changes. The emission cross-sectional area and the absorption cross-sectional area are σem (3.87 × 10-20 cm2) and σabs (4.25 × 10-20 cm2). The fluorescence decay characteristics of the sample at 3.9μm at the 2H11/2 level were investigated and the fluorescence lifetime was calculated. The gain performance of the sample was calculated and analyzed, which can reach 4.25 × 10-20 cm2. Those results prove that Nd3+/Yb3+co-doped fluorobromide glass is the potential mid-infrared laser gain material.