The use of Pr³⁺co-doping for great enhancement of mid-infrared (mid-IR) emissions at 2.9 μm and 2.4 μm is investigated in the Ho³⁺/Pr³⁺co-doped LiYF₄crystals. With the introduction of Pr³⁺ions, the fluorescence lifetime of Ho³⁺:⁵I₇level is 2.15 ms for Ho³⁺/Pr³⁺co-doped crystal, and the lifetime for Ho³⁺singly doped crystal is 17.70 ms, while the lifetime of Ho³⁺:⁵I₆level decreases slightly from 2.11 ms for Ho³⁺:LiYF₄to 1.83 ms for Ho³⁺/Pr³⁺:LiYF₄. It is also demonstrated that the introduction of Pr3+ greatly increases the mid-infrared emission of Ho³⁺:⁵I₆→⁵I₇which depopulates the Ho³⁺:⁵I₇level, while it has little influence on the Ho³⁺:⁵I₆level, which is beneficial for greater population inversion and laser operation. The analysis on the decay curves of the 2.0 μm emissions in the framework of the Inokuti- Hirayama model indicates that the energy transfer from Ho³⁺to Pr³⁺is mainly from electric dipole-dipole interaction. The calculated efficiency of energy transfer from Ho³⁺:⁵I7 to Pr³⁺:⁵F₂level is 87.53% for Ho³⁺/Pr³⁺(1.02%/0.22%) co-doped sample. Our results suggest that the Ho³⁺/Pr³⁺co-doped LiYF₄single crystals may have potential applications in mid-IR lasers.