Ho³⁺with various concentrations and Tm³⁺with molar concentration of 1.28% are co-doped in LiYF₄(YLF) single crystals. The luminescent properties of the crystals are investigated through emission spectra, emission cross section and decay curves under the excitation of 808 nm. The energy transfer from Tm³⁺to Ho³⁺and the optimum fluorescence emission of Ho³⁺around 2.05 μm are investigated. The emission intensity at 2.05 μm keeps increasing with the molar concentration of Ho³⁺improved from 0.50% to 1.51% when the molar concentration of Tm3+ is kept at 1.28%. Moreover, for the co-doped crystals in which the molar concentrations of Tm³⁺and Ho³⁺are 1.28% and 1.51%, respectively, the maximum emission cross section reaches 0.760×10^-20cm²and the maximum fluorescence lifetime is 21.98 ms. All the parameters suggest that these materials have more advantages in the future 2.0 μm laser applications.